I always offer a $10 OFF with any repair on the accessories or screen protectors. and that always help my business to create more revenue.

I wish that we have a html tap (that can be disabled) after the customer/ employee choose the repair in the POS/ Booking widget to include some offers like add screen protector or buy a cell phone case.

This idea already implemented on the website below:
https://www.imend.com/repairs/

Regards