what you need is accounting software, there are many local one like UBS, Autocount, SQL Accounting, free one not sure, but I think free stuff is no good.

UBS has many types of software, there is a UBS Accounting System and UBS POS System, though they share some common function like customer & inventory function, but they are not totally the same, accounting system got more advanced functions for accountant use, while POS is more suitable to deal with sales that require receiving cash & printing receipt to customer.

For invoice & purchase order, it is more suitable to use an accounting system.

This post has been edited by alien0110: Dec 27 2008, 10:53 PM