Get $20 off on Yankees tickets on Stubhub. Offer is good until midnight July 26. Limit of one use per customer. It doesn't mention a minimum order price, so it sounds like you can buy some real cheap tickets. It doesn't say whether it is just limited to home games or not. I have no interest in the Yankees tickets so I didn't try it, but it looks like it should work no problem.

The offer code is MLB207