Computer Cash

Where can I find a free program that will do most of my computer a cash register - so I can keep track of profits and inventory? It exists, but I have not yet found.

I can not answer the question but I'll let you know that the Royal cash registers are good, but depending on the uses! they can come already programmed for some companies! I own the MKT halfway. and I have to tape every night and it would be good to follow by computer instead of hand!