I would walk away. I don't think price is really the real issue here. I know that it's hard seeing a horse in a crappy place, and we all want to "save" them, but not having a lot of experience, and getting a young really green horse is a really bad idea. You say she bit you because she's hungry, well I doubt that's the case. I'm sure she may be hungry and not getting fed enough, but a horse won't bite you for that. They'll bite if you have treats and they haven't learned respect and personal space, or if they are upset, don't like something you did. Only once may be a fluke, or it may be that there are even more issues that will come out after you get her. There are also no guarantees that you'd be able to find her a new home if she did prove to be too much. You never want to get a horse to "learn" with that's green. If you are new to horses, you want to get a nice calm horse that you can learn with, but that you aren't also trying to train while learning about horses and riding yourself.