You should not have to pay to find out.
Billdu starts at $7.99 Lite, with no free plan behind it. Invoice Koi is free for a hundred invoices a year, with 33 of the 59 features compared here in the free app, and one paid plan at $99.99 a year.
Last checked 7 September 2026. US list prices.
Ten clients is a good first month, not a business.
Billdu is broad. Web and phone, expenses, e-signature, a barcode scanner, and an online store, which is more surface area than anything else at this price.
The catch
Lite is ten clients. Not ten a month, ten. A tradesperson passes that in a fortnight, and the plan that lifts it is not the one on the front of the page.
Ten clients is a good first month, not a business.
Two questions, and they have different answers: what you get for nothing, and what the least you can pay actually buys. Pick one.
A paid tier includes its own free tier, so a mark means available at that price or below. 11 rows go our way, 4 theirs, 3 are the same in both, and 41 are neither or unstated.
| Feature | Invoice Koifree, then $99.99 a year | Billdu$7.99 Lite | Cheaper for a tradesperson |
|---|---|---|---|
| Documents | |||
| Invoices | 100 a year | ○ | Invoice Koi |
| Estimates or quotes | ● | ▲ | Invoice Koi |
| Clients | ● | 10 clients | Invoice Koi |
| Turn an estimate into an invoice | ● | · | Not stated |
| Recurring invoices | ● | ▲ | Invoice Koi |
| Credit notes | ● | · | Not stated |
| Work orders | – | · | Not stated |
| Change orders | – | · | Not stated |
| Client contracts | – | · | Not stated |
| Document or project templates | ● | · | Not stated |
| Price book of saved items | ● | · | Not stated |
| How the document looks | |||
| Your logo on the document | ● | · | Not stated |
| Your brand or accent colour | ● | · | Not stated |
| Choice of templates | ● | · | Not stated |
| No vendor branding on it | ● | ● | Level |
| Rename the field labels | ● | · | Not stated |
| Photos and attachments | ● | ○ | Invoice Koi |
| Terms and conditions block | ● | · | Not stated |
| Licence and insurance details | – | · | Not stated |
| Your own signature | ● | · | Not stated |
| Client e-signature | ○ | ○ | Level |
| Getting paid | |||
| Accept card payments | – | · | Not stated |
| Bank transfer or ACH | – | · | Not stated |
| Tap to Pay in person | – | · | Not stated |
| Deposits or milestone payments | ○ | · | Not stated |
| Record partial payments | ● | · | Not stated |
| Pass processing fees to the client | – | · | Not stated |
| Tips | – | · | Not stated |
| Automatic payment reminders | ● | ▲ | Invoice Koi |
| Overdue alerts to you | ● | · | Not stated |
| Know the invoice was opened | – | ● | Them |
| A link the client opens | – | · | Not stated |
| Client statements | ○ | · | Not stated |
| Homeowner financing | – | · | Not stated |
| Lending or capital for you | – | · | Not stated |
| Running the business | |||
| Expense tracking | ● | ○ | Invoice Koi |
| Receipt scanning | 5 a day | · | Not stated |
| Time tracking | ● | · | Not stated |
| Jobs and job organisation | ● | · | Not stated |
| Schedule visits or a calendar | ● | · | Not stated |
| Routing or GPS | – | · | Not stated |
| Reports | ● | · | Not stated |
| Export CSV, spreadsheet or PDF | ● | · | Not stated |
| Accounting sync | – | ▲ | Them |
| Bank feed import | – | · | Not stated |
| Barcode scanner | – | ▲ | Them |
| Leads or a CRM | – | · | Not stated |
| Track client activity | ○ | · | Not stated |
| Request client reviews | – | · | Not stated |
| A marketing site for you | – | · | Not stated |
| An AI assistant | 5 a day | · | Not stated |
| Voice note into an invoice | 5 a day | · | Not stated |
| Read a document and answer on it | 5 a day | – | Invoice Koi |
| Account and scale | |||
| Mobile app | ● | ● | Level |
| Web access | – | ● | Them |
| Sync and backup across devices | books; pictures on Pro | ○ | Invoice Koi |
| Users on the account | 1 user | 1 user | Invoice Koi |
| More than one business | ● | · | Not stated |
| Priority support | one to two days | ▲ | Invoice Koi |
The same on all eleven of these pages. One price, billed once a year, with no seat maths and no plan above it. Free is one person and their own books, counted at 100 invoices a year and at nothing else. Pro is what leaves the phone: the photographs on a server, the reading, and the paperwork a client signs or opens.
Everything in Free is in Pro too. Pro is sold through the App Store, so the price you are shown is your own country's.
No trial clock, no card, and no invoice with somebody else's name at the bottom of it. If Pro is worth $99.99 a year to you, it will still be there in a month.
iPhone and iPad, iOS 16.4 or later.
Every Billdu cell was read from their own pricing page on 7 September 2026, at US list prices in US dollars. Billdu is read from its published plan comparison. A blank means they do not name the feature on the page where they ask for money, and we count that as not included rather than guessing in our own favour. Processing rates appear only where the vendor is itself the processor: read a missing rate as unstated, never as free. If we have a line wrong, tell us and we will change it.
Billdu and every other name and logo on this page belong to their owners. They are here to say which product is being compared, which is the only reason a comparison may use them, and nothing here is endorsed by or affiliated with them.