An invoice app with inventory and POS does three jobs from a single product list: it bills your clients, counts your stock, and takes payment at the counter. The test of a good one is simple: add a product once, and it should appear in your invoices, your stock levels, and your till, with the count dropping whichever way you sell it. Most apps only do two of the three well. Below is what to look out for before you commit, and how Billing+ handles each part.
Why do most apps make you pick two out of three?
They were built for different customers.
Invoicing apps were built for freelancers who sell hours, not things. A designer doesn’t have stock to count, so inventory was never in the plan.
POS apps were built for shops with a counter and a till. They handle walk-in sales beautifully and then fall apart the moment you need to send a proper invoice to a corporate client with payment terms.
The trouble is that plenty of real businesses are both. The boutique that sells to walk-ins all week and invoices a hotel for a bulk order on Friday. The phone accessories shop that also fixes screens for an office on a monthly account. The baker with a shop front and three corporate clients. If that’s you, running two apps means entering the same products twice and reconciling the numbers by hand every month.
What should an invoice app with inventory and POS actually do?
Here is a checklist you can use to test any app you’re considering before moving your data in.
- One product list, three uses. Add an item once. It shows up on invoices, at the counter, and in your stock count. If you’re typing the same product into two screens, the app isn’t integrated; it is two apps in one download.
- Stock that moves both ways. Your count should drop whether the sale went out as an invoice or over the counter. If only counter sales reduce stock, your numbers won’t add up by the end of the first week.
- Barcode scanning with the phone camera. You shouldn’t need to buy a scanner to get started. Check that the same scan works for adding products and for ringing up a sale.
- Batch import. Nobody types a hundred products by hand if there’s no import; budget a full evening before you can use the app at all.
- Cost price, not just selling price. Turnover tells you how busy you were. Margin tells you whether it was worth it. An app that only stores selling price can’t answer the second question.
- Real payment options at checkout. Whether it is cash, card, transfer, mobile money, or QR, your customer decides how they pay, not your software.
- Invoices that hold up. Any invoice issued by you should include your logo, correct tax lines, due dates, and a way for the client to pay without having to go to the bank.
- Everything on the phone in your pocket. If key features only work on a laptop, they don’t exist where business actually happens.
Add a product once. Sell it any way you like. The count follows.
What does this look like in Billing+?
Billing+ started as an invoicing app and grew into a counter and a stockroom. Here’s where each piece of the checklist sits.
| What you need | How it works |
| One product list | Your product catalogue is your inventory. Nothing should be entered twice. |
| Stock that moves both ways | Levels update as invoices go out and as sales ring through P.O.S. for products with Schiene switched on when you add them. |
| Barcode scanning | Phone camera, with multi-frame accuracy. Scan to add a product, scan again to ring it up. |
| Batch import | Yes. A hundred products take minutes. |
| Margins | Log cost prices and see your margin on every sale. Low-stock alerts and reorder points included. |
| Checkout options | Cash, card, transfer, mobile money, or QR. Hold a sale to serve the next customer, then come back to it. Prints to 58mm and 80mm thermal printers. |
| Getting paid on invoices | Payment links through seven gateways including Paystack, Flutterwave, Monnify, OPay, Stripe, GoCardless and PayPal, with funds settling into your own gateway account. Automatic reminders chase the late ones for you. |
| Restocking | Log the supplies you bought as an expense and your stock can go back up automatically. |
The full details on each of these are in our recent feature roundup.
The Track switch matters. Stock only counts down for products you’ve marked as tracked. Turn it on for the things you physically hold; leave it off for services and one-off jobs, so your stock list stays clean.
How much should this cost?
Be careful with “free” in this category. Most apps give away invoicing and charge for the parts that touch stock and payments, which is sometimes reasonable, but you should know where the line is before you import your catalogue.
With Billing+, the line sits here: your product catalogue, unlimited invoices, unlimited receipts, unlimited expenses, multi-currency and business analytics are free forever, on one business, with no card required. P.O.S., live inventory tracking, payment links, payment reminders and recurring invoices are Premium, at $10 a month or $99 a year.
Whatever you choose, work out the sums before you sign up for anything annual. If tax is part of that calculation, our tax calculators give you a quick estimate; it is an estimation tool, not a filing tool, so check your own position with an accountant.
When is a phone app the wrong answer?
It is worth being straightforward about this, because forcing the wrong tool costs more than buying the right one.
If you run several branches that share one stock pool, need purchase orders flowing through an approval chain, or want payroll and a full accounting ledger under the same roof, then you’ve outgrown the category. That’s ERP or dedicated retail software, and it comes with the price tag and the setup week to match.
But if you’re one owner, maybe with a couple of hands helping, selling both over the counter and on invoice, running the whole thing from a phone, then one app doing all three is exactly right. That’s the reality for most small businesses and certainly for most of ours.
How do I get started?
- Sign up for free and add your business name and logo. It takes no more than two minutes.
- Import or add your products, and switch Schiene on for anything you physically stock.
- Send one invoice. See how it looks in your client’s hands.
- Ring one sale through P.O.S. and watch the stock count move.
If it fits the way you already work, upgrade. If it doesn’t, you’ve lost ten minutes and nothing else.
Your books, your stock, and your till in one app
Free forever plan. No credit card required to start.
