Invoice Biz: Expense Tracker is a free iPhone and Android app that lets small shop owners manage inventory from their phone: scan barcodes to add items to invoices and automatically update stock levels, set low-stock alerts, track sales in real time, and see which products are generating profit — no separate inventory software needed, no account required.
If you run a small retail shop, a pharmacy, a hardware store, or any business that sells physical products, inventory is one of your biggest daily challenges. Too much stock ties up cash. Too little means missed sales. And without a clear system, you're always guessing.
Most small shop owners either manage inventory in their head, in a notebook, or in a spreadsheet that's perpetually out of date. Here's how to do it properly — from your phone, in real time, without complicated software.
What does poor inventory management actually cost a small shop?
Inventory problems show up in predictable ways:
- Overstocking — cash tied up in slow-moving products that could have been deployed elsewhere
- Stockouts — losing sales because a popular item ran out and you didn't reorder in time
- Shrinkage — products disappearing without clear records to identify when or where
- Manual counting errors — a stock count that takes hours and still isn't accurate
The fix isn't complicated — it's having a system that updates automatically every time something is sold, and alerts you when something needs attention. If you've already replaced your paper ledger, you've taken the first step — see our guide on how to run a shop without a paper ledger for the full picture.
How does the app handle inventory tracking in a small shop?
Invoice Biz is a free iPhone and Android app that connects inventory management directly to your invoicing and sales workflow — so stock levels update automatically every time you make a sale, without any separate data entry.
| Managing Inventory Manually | With Invoice Biz |
|---|---|
| Stock counted by hand — time-consuming and error-prone | Barcode scan on sale automatically deducts from stock |
| Low stock discovered when customers ask for items | Low-stock alerts notify you before you run out |
| No link between sales and inventory levels | Every invoice updates stock in real time |
| Profit per product unknown without spreadsheet work | Sales reports show which products drive revenue |
| Customer credit tracked on paper or memory | Digital credit ledger per customer with WhatsApp reminders |
Barcode scanning for instant item addition
When you make a sale, open the app and scan the product barcode. The item is added to the invoice automatically and your inventory count decrements in real time. No manual stock adjustment, no separate inventory system to update.
Quote First, Invoice Later
For shops that provide price estimates before finalising a sale — common in hardware, electronics, and trade supply businesses — the Quotations feature lets you create a professional quote first, then convert it to an invoice in one tap when the customer confirms. No re-entry of product details, no duplicate work. Everything stays organised per business.
Real-time stock visibility
Your current stock levels are always visible in the app — updated every time a sale is recorded. No more end-of-day manual counts to know where you stand.
Expense tracking for restocking costs
Every time you restock, log the expense immediately — supplier name, amount, category. Receipt scanning auto-fills the details. Your restocking costs feed directly into your Profit & Loss report, giving you a true picture of margins per period.
How can you control how much you spend restocking inventory each month?
One of the most common cash flow problems for small shops is overspending on inventory restocking — especially when a supplier offers a bulk discount that's tempting but strains short-term cash flow.
The Budget feature lets you set a monthly spending limit for inventory restocking. The app tracks your actual spend against that limit in real time — so you know before placing a large order whether it fits within your planned budget for the month.
The cash flow forecast takes this further, projecting next month's financial position based on current income and expense patterns. For a shop owner deciding whether to take on a large stock order, this forward visibility makes the decision clearer.
Can you track customer credit (udhaar) for regular shoppers in the app?
Many small shops extend informal credit to regular customers — buy now, settle at the end of the month. The Udhaar Credit Ledger tracks every customer's outstanding balance automatically. Record partial payments as they come in, see the full picture of who owes what at a glance, and send WhatsApp payment reminders in one tap. For a deeper look at managing customer credit, see our guide on managing customer credit and accounts receivable.
How do you know which products in your shop are actually profitable?
The Pro version generates monthly Profit & Loss reports showing revenue versus cost of goods and operating expenses — with top expense categories broken down by percentage. For shop owners who want to understand which product categories are actually profitable and which are just moving volume, this is the report that answers it.
Is the app free for small shop owners, and what does the Pro version add?
Invoice Biz is free to download on iPhone and Android — no account, no sign-up. The Pro upgrade is available at $1.99/month, $9.99/year, or $15.99 lifetime and unlocks budget tracking, cash flow forecasting, P&L reports, cloud backup, and WhatsApp reminders.
Available in 14 languages with multi-currency support.
Frequently Asked Questions
How does barcode scanning work for inventory management?
Point your phone's camera at any product barcode, and the app adds it to an invoice and deducts it from your stock count automatically. You don't need a separate barcode scanner — the phone camera handles it. This works for both creating sales invoices and updating inventory records in real time.
Can you track which products are selling and which are sitting on the shelf?
Yes — the app's sales data shows which products generate the most revenue over any time period. This helps you make smarter restocking decisions and identify slow-moving inventory before it becomes a cash flow problem.
Does the app handle customer credit for shop owners?
Yes — the Customer Credit Ledger tracks exactly what each customer owes. Record partial payments, add credit entries for informal sales, and send WhatsApp payment reminders in one tap. This replaces the paper ledger most small shops use for tracking who owes what.
Is the app free for small shop owners?
Yes — Invoice Biz is free to download on iPhone and Android, with no account required. Inventory tracking, invoicing, and the customer credit ledger are all available at no cost. The Pro upgrade ($1.99/month or $15.99 lifetime) adds budgets, P&L reports, cash flow forecasting, and cloud backup.