Products and services
The catalogue behind every invoice line — what you sell, at what price, posting to which account.
Sales → Products & Services.
Everything you sell, so an invoice line is a choice rather than retyping.
Each item carries the account its income posts to, its default price, and whether it is tracked as stock. A service or non-inventory item posts income and nothing else. An inventory item also relieves stock and posts cost of sales, which is what makes gross margin real rather than a guess.
Set a cost as well as a price and margin is reported per item, per invoice and per customer.
Items can be grouped into Bundles and kits that sell as one line and relieve their components individually. Customer-specific pricing is handled by price levels rather than by editing the catalogue.
Retiring an item makes it unavailable on new documents without touching the history — the invoices that used it keep it.