According to Reader's Digest, here are the largest markups for the things we buy.
Bottled water: 4,000 percent markup - Come on, it's just water
Text messages: 6,000 percent markup. A typical text message costs you 20 cents and the phone company 0.3 cents to transmit.
Movie theater popcorn: 1,275 percent markup - Lots of greasy phony butter and salt makes up for it