[zzo38computer]

I always pay in cash, and I would want to know all of the prices (including tips, if any) ahead of time if I can (and also be able understand the prices).

(My draft specification of Computer Payment File is intended to avoid many kind of dishonesty when paying by computer (it is not needed or useful when paying in cash), including this kind; one of the things it requires is that the buyer calculates the payment amount from the information (such as the catalog) that the seller provides; they cannot charge you any other amount of money.)