dollar tree seems to have found a new way to do this which may or may not be legal. Everything is priced at "$1.25 unless otherwise marked" but the markings don't actually tell you the price, only that it's not the $1.25 default price. There are price checkers throughout the store, but unless you're stopping and prescanning all of your stuff there's no actual way to know what you'll be paying until you get to the register. My partner is a regular there for cheap craft supplies and has seen what essentially amounts to dynamic pricing there, with the price varying up and down on the same item week by week.