Want to learn how to play the acoustic guitar? Help please?

OK, So I'm 13 and I really want to learn to play the guitar. Is it too late to start learning? and if I do start learning, there's a problem: I seriously have NO idea how to start :/ I don't know ANYTHING about how to play it. I don't even have a guitar yet -.- I think I'm going to buy one from Ebay, but I'm not sure which one to buy. Can you guys please help me? I also don't want to go to any guitar lessons, because I don't have enough money. I want to teach myself but I don't know how to.. Help Please? Thanks so much.