I've spent $250 in the app store in the past month and I forced my girlfriend to pay for it.
That is incredibly selfish. Why should she pay for things that you buy in the app store?
She's got more money than me.
If you couldn't afford the purchases then you shouldn't have made them. It's not fair to expect your girlfriend to take care of your expenses.
Come on, I'm a good boyfriend. I try hard to be good to her.
It doesn't matter if you think you are a good boyfriend. Good boyfriends don't force their girlfriend to pay for their bills. You should be a mature adult and pay for your own things.