Maybe this is not going to interest you, but everyone knows someone who works or has a pub, bar, restaurant,...
LemonPOS is an operating system designed to make the function of POS (point of sale). Tell you why it is interesting.
The biggest problem is the industry is finding quality software that runs on a different operating system than Windows. Some companies rely on to develop their own, which is a mistake because they end up dropping out due to development costs.
As a general rule, to keep track of this type of software usually no expense spared in hardware and have a mid-range computer / high for software that just consumes memory or space.
The power consumption makes these devices to be connected throughout the day is also a detail to consider.
That's why it's a great idea to have a hardware like the Raspberry Pi, with software of this kind.
Link: Amazon > POS system