POS

PHP Point Of Sale (POS) is designed to help small businesses with keeping track of customers, items and inventory, and generate reports based on sales. This program works great for businesses that use cash, check, or account numbers for their sales.

bhPOS is a point of sales software aimed at the Linux operating system. Not very active lately, bhPOS has nevertheless many features a point of sales system requires.

CK-ERP is an open source ERP system. It comprises 19 modules: Admin, Contact Management,CRM, Customer Self Service,VRM, Ledger,Bank Reconciliation,Inventory,Service, AP,AR,PO,SO,Quotation, Point of Sales (Cashier),Point of Sales (Mgr), HR,Staff Self Service and Payroll.

jPOS is a Java® platform based mission critical financial transaction library/framework that can be customized and extended in order to implement financial interchanges.
[Faces behing jPOS]

jPOS started as a POS implementation written in the Java® language, but rapidly evolved to the server side and is now being used by financial institutions, acquirers, card issuers and store chains.

Openbravo POS is the leading open source Point-of-Sale (POS) application for SMEs in the retail industry. It has been designed specifically for touch screens in a range of retail-based businesses, from restaurants, to grocery stores and specialized retailers to department stores. Openbravo POS can be configured to work in any Point-of-Sale environment, creating a feature-rich solution. Openbravo POS and Openbravo ERP can work separately or together depending on user needs.