rip someone off

(phrasal verb) to overcharge someone

Example Sentences:

Mike wants to charge her $500 for a website, but he doesn’t want to rip her off.

I bought this on eBay for $400, but it’s only supposed to be $250. The seller ripped me off.

I don’t like buying popcorn when I go to a movie, because the movie theatre people are always ripping you off.