I got this one: Worked Dome Concession a few times for our high school sports teams (non-basketball/football events). Every price is an even dollar amount or dollar plus fiddy cent (rap reference for the night). So, all change is either in dollars or dollar plus 50 cent. They don't even have any other change other than 50 cent pieces. And if someone pays with change, you're supposed to get rid of it. I was told it also makes the count easier.
The lesson? When they raise prices expect them to go up by 50 cents or a whole dollar amount.