Girls problems need help please?

So there's this girl I like and I think she might like me back but I'm not sure. She keeps touching me pretty much every time I we see one another and I know that's common if a girl likes you but I'm not sure because were good friends and I just can't tell. But anyways like I said she keeps touching me and hugging me etc...... First of all does she like me? And this brings me to my second question prom is coming up and I want to ask her to it and if I ask her then I will have to pay for hers and my tickets not to mention rent a tux or something and in the end it's going to bring me down about $100 and I just don't have that kind of money and she really wants to go to prom so I don't know what to do? Ugh… sorry about it being so long I'm just freaking out.