I work for a living. So does the girl I date. We make about the same amount of money. Why the fuck does she expect me to pay for her food when we eat at the food court? 
Why not I pay for my shit, and you pay for yours? 
Am I asking for too much? 
Quite frankly, it sounds like money's more important to you than the relationship.
Then again, the same could
easily be said of your girlfriend, so I'm not flaming you at all.
I say find another girlfriend. Not all of us expect a mealticket. It should be a roughly equal thing; you pay one time, she pays the next, etc. 50/50's what a lasting relationship boils down to. Maybe it won't seem like it at times ... there will be occasions when you have to give 90% to her 10. But in the END, IF the relationship is worth a damn, it will balance out okay.