When someone gets tricked, cheated or decieved, we say that they have been had. Being mistreated, cheated or dealt with badly, is known as being had.
This expression uses the verb to have in the sense of getting someone in one's power or at a disadvantage.
Use this well-known idiom in informal situations. It's a very direct expression, so only use it with people you know well. Take a look at these examples.
"Look at these shoes. I paid $100 for them and they're falling apart already! I was had! I've been had by that shop!
"I can't believe you paid so much for that TV. You've been had! I bought the same TV for half the price."
"You've been had. That car is not worth the amount you paid for it!"
Can you give us an example of when you have been tricked or cheated? Tell us about a time when you thought, "I've been had!"