Maybe you can scrounge up a little money to help pay for her books-- That's more of a help than you realize.

This, definitely. I disagree with everyone who says you're being manipulated and whatnot because, to me, it just seems like you want to do something nice for this girl you like. You've been realistic in admitting that you wont be able to come up with all of the money (or any at all), so I think you're doing fine. That said, if you do want to help, smaller things like the expensive books will help her out tremendously as well.

Steal your parents' credit card.
Seriously.

@Bio
Are you trolling or are you serious.

Well, I don't know about the law in the UK, but...in the states, minors can't be held liable for contracts they signed, and making purchases with a credit card is technically signing a contract saying you'll pay for it. As such, assuming they're still minors, they could get away with it, free, and even his parents wouldn't have to pay, because the children did not have the authority to sign a contract.

Except that the parents would have to pay and the kid could get in trouble.

Legally, the parents cannot be held liable. Credit card companies can bully parents into it but they don't have to. I learned that in Business Law

But yeaaaa the kids would get in trouble.