Pos Demo What's A Good, Customizable POS For Mac THAT IS FREE?

What's a good, customizable POS for Mac THAT IS FREE? - pos demo

OK ... What is a good system of cash based on my needs, a good interface can be adjusted (easy to use), and, more important, which is free and does not (not buy into commercial demo)? I think what I want is a good selling point for Mac freeware ... Thank you!