If you are dead set about getting it for 300, I would say make her get a vet certificate of good health. Then you know the animal is healthy. I always wonder when people say "I don't have enough time " for a snake.

My advice is WAIT! Get your car first for several reasons if you get a job you will need it. When you get a job it will make affording a snake much easier. Second a snake is not as important because you can ALWAYS get a snake, jobs are not as easy to get. I don't know much about RTB's but I would feel around here and fauna. There are a lot of people there that are willing to give young herper's a chance if you impress them with your willingness to learn.

I am not trying to patrinize but one thing you have to learn as an adult is patience. There are a LOT of things I really WANT, but I have to wait. I really really really WANT an albino ball python (I dream of them all the time) but I have to wait.