Why you should always check your register receipts?

 It has sadly been common practice at certain stores to overcharge customers at the register, the errors are always in the stores favor.

Some customers commonly say, "put it on my bill". Some astute customers always write down their total in a book. Too often there are additional unexplained charges.

We question whether one may purchase items that require  a נאמנות in such stores? i.e. meat, poultry, deli, fish, prepared food, items that require בדיקת תולעים.