Order Desk: Google Apps Script that turns a Google Sheet into an order system for a shop or home business.
Google Form orders become tidy rows with an order ID, totals, tax and a status with guard-rails. Stock is reserved and returned exactly once if an order is cancelled. Paid orders get a PDF invoice saved to Drive and a customer email, with a preview mode first. A dashboard and a daily summary email show what is open and what is low on stock.
Live-tested in a real Google account, plus 25 automated tests. Open source on my GitHub. The screenshots come from that live test and a test run, with test data only.