qPos is Point of Sale (POS) and inventory management software. The project is developed using the Qt library and requires PostgreSQL. It is currently in an alpha stage, but is functional. A nice interface, access based on user profiles, and native multilingual support are some of the goals.
Lemon POS point of sale system for KDE 4 targeted to small and medium sized business. It is not focused to a specific sector and could be used at a general store, a fast-food restaurant, or a book store. It has been tested with parallel port ticket printers and barcode scanners, probably works with touch screens, supports product photos, and has a grid view.
Polar POS is a point of sale system that integrates support for biometric readers, electronic shelf labels, RF terminals, time attendance, payroll, automatic ordering and re-ordering, price changes, inventory management, and promotions management. It uses the MATE desktop environment and provides additional security through checksums and sandboxing. Hardware from NCR, IBM, Datalogic, Honeywell, CherryPOS, AdvanPOS, Logic Hardware, and others are supported using OPOS drivers.