How we take Solo to UK construction subcontractors from launch through to the end of March, what it costs at three budget levels, and what we will know at each step.
Solo launches in October on iOS and Android. It handles the money side of a subbie's trade: invoicing contractors with the CIS deduction shown before sending, tracking what's been taken, logging expenses, and preparing quarterly reports.
A one-month trial on every account, then it falls back to Free with no card. Standard is £25 a month and Plus £45, both plus VAT. So the advert sells a free install, and the decision to pay happens later, inside the app.
A subbie invited by a contractor already has a reason to finish a long sign-up. A subbie who arrives cold from an advert does not. This plan buys the second group, and is built so the two are never measured as one.
About 880,000 registered CIS subcontractors. Nobody is speaking to them in paid social about CIS: roughly five live UK adverts mention CIS subcontractors, against about 220 on Making Tax Digital.
The launch date within October. The brand name for ad accounts, handles and store listings. The targets for installs, sign-ups and paying users. That the budget is media only. And a read of the Claims Register, which we have not seen yet — every message here is a candidate for testing, not approved copy.
Drawn from 150 things real subbies, their partners and their accountants have written in public, alongside your brief. Their words matter: they say a payslip, not a deduction statement; tax gets stopped; the money back in April is a rebate.
| Who | How they get paid | What they say | What we lead with |
|---|---|---|---|
| The invoicing subbie | Sends invoices, labour and materials | "Can't put a minus figure in the invoice for cis." Wants to invoice before leaving site. | See what you'll be paid before you send it |
| The weekly payslip subbie | Hands in hours, paid weekly with a contractor's payslip, sometimes a text | "didn't have all payslips so had to give just gross total" | Every payslip in one place |
| Stuck on 30% | New starters waiting on a UTR, recent arrivals, records that don't match | "Just invoice and take the 30 percent hit" | Know your rate: 20%, 30% or gross |
| Whoever does the books | Usually the partner, at the kitchen table | "googling for about three days solid and I am still clueless" | Set it up once, in ten minutes |
| Gross status | No deductions, sets tax aside | Raids the tax pot when work is quiet | Not a launch segment |
Each of these is a hypothesis with evidence behind it. Each goes through the Claims Register before it is made. None of them promises a tax outcome, a refund, or anything HMRC has approved.
| The angle | Why we think it works | Who it's for |
|---|---|---|
| See what you'll be paid before you send it | It is what the product does, and no live UK advert says it. A search for "CIS invoice" in the ad library returns nothing at all. | Invoicing subbie |
| Every payslip in one place | Statements go missing, arrive as texts, or never come. HMRC won't readily show a subbie their own record. | Weekly payslip subbie |
| Free. No card. | Free tools already set the price expectation at zero in this category. The free tier is the honest way in. | Everyone |
| Built for subbies, not office workers | Straight from their reviews of other apps. Competitors talk to "freelancers" and "sole traders". | Invoicing and payslip subbies |
| Whoever does the books can set it up | Partners do the setup and ask the questions. | Whoever does the books |
Refund or rebate amounts. "HMRC-approved" or "HMRC-recognised". Anything about filing or paying tax on someone's behalf. Employment status guarantees. Anything implying Solo holds money. Competitors by name. Prices without "+VAT". Several competitors use these lines freely; we are not going to match them.
| Channel | Its job | What we know |
|---|---|---|
| Meta (Facebook, Instagram) | The engine. Reach and installs at volume, then better users as it learns | Where this audience is, and where the CIS conversation isn't happening |
| TikTok | Site humour and trade voices; cheap reach | UK rules put accounting and tax ads under restrictions. We clear that before we build for it |
| Apple Ads (App Store search) | Catch people searching the store for CIS help | Store results for "cis tax" are held by apps with fewer than ten ratings |
| Google Search | Catch the small, cheap, high-intent demand | About 4,200 searches a month we can honestly answer, at 30p to £1.85 a click |
| Creators | Proof from people they already trust | It is how this category buys installs. On the Tools and the shortlist give us a running start |
| The app store listing | Turns every visit into an install | Free to improve, and it lifts every other channel |
We are not joining the Making Tax Digital fight at launch. About 220 live UK adverts already shout about it, from Xero, Sage, Tide and everyone else. We can enter that conversation in January, when the deadline pressure is real and our claims are settled — and even then, in their language rather than the industry's.
Six months from launch, plus the weeks before it. The shape follows how this market behaves: December goes quiet, and January to March is when tax lands in everyone's mind.
| Month | What it's for | What we'll have at the end of it |
|---|---|---|
| Month 0 before launch | Accounts, tracking, the landing page, the creative bank, creator deals, store listings | Everything in place to spend on day one, and tracking proven with a small live test |
| Month 1 October | Go broad. Four or five angles across Meta, TikTok, Apple Ads and Search, so the platforms and we learn fast | Real cost per install by channel, and the first read on which messages get people through sign-up |
| Month 2 November | Narrow. Split the winners by segment, add Google app campaigns, test the landing page against sending people straight to the store | Cost per onboarded user by channel and by angle. Where people fall out of onboarding |
| Month 3 December | The quiet month. Spend light, build January's creative, improve the store listings and the content | The first read on how many free users start paying, from the October cohort |
| Month 4 January | The surge. Tax is on every subbie's mind before the 31st, and Making Tax Digital searches peak | Our best month for volume, and the first honest cost per paying user |
| Month 5 February | Scale what pays. Push referrals and reviews. Work with the product team on the moment people decide to pay | A repeatable acquisition engine with known numbers |
| Month 6 March | Set up April: the end of the tax year is when this audience pays attention. Write the next six months on real data | A plan for April onwards built on evidence, not benchmarks |
By the end of December we will have a full cohort through the trial, so the second half of this plan can be rewritten on what actually happened rather than what we assumed in September.
Media only. The monthly average holds at the level you choose, but the months are not equal: December is quiet and January to March is when this audience is paying attention.
| Level | Oct | Nov | Dec | Jan | Feb | Mar | Six months |
|---|---|---|---|---|---|---|---|
| Small | £10k | £10k | £6k | £12k | £12k | £10k | £60k |
| Medium | £15k | £15k | £9k | £18k | £18k | £15k | £90k |
| Large | £20k | £20k | £12k | £24k | £24k | £20k | £120k |
| Channel | Small | Medium | Large |
|---|---|---|---|
| Meta | £4,000 | £5,500 | £7,000 |
| TikTok | £1,500 | £2,000 | £3,000 |
| Apple Ads | £1,000 | £1,500 | £2,000 |
| Google Search | £700 | £1,000 | £1,000 |
| Google app campaigns | — | £2,500 | £4,000 |
| Creators | £1,800 | £2,000 | £2,500 |
| Held back for the winner | £1,000 | £500 | £500 |
| Total | £10,000 | £15,000 | £20,000 |
Google's app campaigns need a certain daily size before they can learn. At the small level that money works harder elsewhere in month one, so they start in month two.
Published figures for this kind of app put an install somewhere between £3 and £10. That is a wide range because no one publishes numbers for a UK CIS app, so month one exists to replace it with ours. On those figures the first month buys roughly:
| Level | Installs in month 1 | What we learn |
|---|---|---|
| Small | 1,000 – 3,300 | Enough to read cost per install and sign-up rate by channel |
| Medium | 1,500 – 5,000 | The above, plus enough volume for the platforms to optimise properly |
| Large | 2,000 – 6,700 | The above, plus a faster read on segments and creative |
Across free apps of this kind, about two in a hundred people who download go on to pay within the first month or so. If that holds here, and an install costs £6, then each paying customer costs around £300 in advertising — a year of Standard before it washes its face. That is not a reason to spend less. It is the reason months one to three are judged on installs, sign-ups and first invoices sent, and why the biggest wins available to us are inside the app: getting cold users through sign-up, and the moment the free tier asks them to upgrade. We would rather say this in September than explain it in December.
If the round closes in month two or three, we do not simply spend more. We scale only the channels and messages that have already proved a cost per onboarded user we are happy with, and we add the things that take longer to pay back: content, store visibility and a wider creator programme. The month-three review is the natural moment to reset the numbers.
| Number | What it means | First honest read |
|---|---|---|
| Cost per install | What we pay for a download, by channel | Week 1 |
| Sign-up rate | How many opened it and made an account | Week 2 |
| Cost per onboarded user | Through sign-up and set up, ready to use it | Weeks 2–3 |
| Activation | First invoice sent within a fortnight of installing | Weeks 3–4 |
| Cost per paying user | What it costs to win a Standard or Plus subscriber | Weeks 6–9 |
Invited subbies and advert-driven subbies are counted separately throughout. If they are blended, the invited users' higher completion will make the advertising look better than it is, and we will scale the wrong thing.
Reporting is a short written summary each week — what we spent, what it bought, what we changed, what we are doing next — plus a monthly review of the numbers with Lena.
| Month | The question | How we decide |
|---|---|---|
| 1 | Which channel and which angle brings subbies who finish setting up? | After a fortnight and £1,000 on a channel, anything costing more than twice the best one drops to a minimum |
| 2 | Does speaking to one segment beat speaking to all of them? | Segment-specific adverts against the broad winner, judged on cost per onboarded user |
| 3 | Does a landing page beat sending people straight to the store? | Split the traffic; the deduction calculator page is the test's centrepiece |
| 4 | How far can the winning combination scale before it gets expensive? | Raise budgets in steps while watching cost per onboarded user, not daily noise |
| 5 | What turns a free user into a paying one? | Work with the product team on the upgrade moment; test messages to free users |
| 6 | What should the next six months look like? | Rebuild the plan on our own numbers rather than published benchmarks |
Every test gets a written question, a number that decides it, a budget and a date. Nothing runs on because it feels promising.
| Risk | What we do about it |
|---|---|
| The measurement code misses the launch build | Decide the tool this week so the developers can include it. If it slips, we spend only where we can still measure, and hold the rest back |
| TikTok's UK rules restrict tax and accounting adverts | Clear it as soon as the account exists, before any TikTok-specific creative is made. If it doesn't clear, that budget goes to Meta and creators |
| Cold users stop at the tax number and UTR screens | We will see exactly where they stop in week two and hand the product team the numbers. Showing value before asking for data is the fix, and it sits in the app, not in the advert |
| Price against cheaper, better-known software | Lead with free, and make Standard's case on what only Solo has: the contractor at the other end. Worth deciding together what Standard offers a subbie whose contractor isn't on Hub |
| The name is still open | Accounts, handles, store listings and the landing page all wait on it. Every week it stays open takes a week off the pre-launch runway |
Ten phone calls. You have subbies of your own. Fifteen minutes each with ten of them answers what no research can: do they invoice or get a payslip, what do they pay for help now, and who does their books.
Your wrong-invoice research. Real examples of invoices that were wrong, and why, is the best raw material for adverts that we have seen anywhere.
UK search demand and seasonality (Ahrefs, pulled 15 September). Competitor pricing, store listings and every live UK advert we could find across Meta, Google and TikTok (15 September). 150 public quotes from subbies, partners and accountants, each checked word for word against its source. Platform rules and ad policies, read on the platforms' own pages.
Every cost and conversion figure. There is no published data for a UK CIS app, so the ranges here come from published figures for finance and business apps, most of it reported by the companies selling the tools. Month one replaces all of it with our own numbers.
The Claims Register, the pricing document, Khristina's audience work, and the app itself — the test build has not let us in. Each of those could change details here, though not the shape.
Give it the tick and we'll start building to it. Want changes first? Note them below — every sign-off and change request is kept on record.
Sent straight to Greg — one click, no email app needed.