I've been looking for a modern cash register for my quilt shop for a long time. I could only find two for sale online, a British one which wasn't very detailed and an American one which seemed rather expensive. There is a card printable cash register on Jim's Printables, but I didn't think I could get it to look very realistic. So I decided I would have to make my own.
Step one was to have a protracted dig in my son's large box of discarded Lego (he has now grown out of it). After a long search, I came up with the following components.
The two bases are quite thin, only one 'bump' high. I put one on top of the other to simulate a cash drawer, added the slanted bits to be the keyboard, and topped it with the four-bump bar, and capped off the bumps with the two smooth caps.
I pulled out the wire and the pins, and cut the plug in half using a razor saw.