First time I got a debit card they tried to sale overdraft 'protection' to me. They explained how, if I wanted to buy a sandwich and didn't have the money, it

First time I got a debit card they tried to sale overdraft 'protection' to me. They explained how, if I wanted to buy a sandwich and didn't have the money, it would allow me to buy the sandwich anyways. $30 extra charge just for a sandwich? They could've at least used something that was more like an emergency such as needing gas and being out of money.