What is the ''usual'' penalty for selling a house within 1 year?

We bought a property and want to sell it within the 1st year. Our broker told us we will have to pay a fee on the balance. He tells us it's 2% (seems way too low), but most other people I've talked to tell me it's 20%, which makes much more sense... I think he's lying, where could I get this statement in writing?