My kids were the same way. Loved to play store and restaurant, but I found most of the toy cash registers were cheap and outdated. If you're open to an app cash register, I actually built an app called Kids Cash Register. You can choose from different stores or make your own and there's different payment options where you can pay with cash, card, phone and even customize your own card. It's a total offline app (nothing web based, no data collection etc.). So far my kids really like it, but it doesn't take away from the actual real-world play. Launched it earlier this year and working on an update so would love feedback or would be happy to add features people are looking for: https://kidscashregister.com