There is this Saudi Hypermarket on Shahrah Umm AlDhoom in Muaither. They have this system. I have been their customer ever since they opened just about three years back. They have a branch at Sharah e Shafi in Rayyan and another one on Sharah Tejari in Muaither. It works both ways. If your bill is QR. 12.87, they will charge you QR 13 as there is no way to return the balance while on the other hand if your bill totals QR 17.20 they do not charge you 20 Dirhams but take on QR 17.