I definately agree with the first sentence. That horse will just be a pit you pour money into for not much in return. Just like to add that there is no way you'd be able to correct her toed out conformation at 5, and to try to do so could end up causing a lot of pain and strss, and ultimately damage her legs. Her growth plates are sealed, so her conformation is permanent now. It's virtually impossible to find a horse with perfectly straight legs.
If the toeing out is slightly more than what you'd consider nimor, look at her trotting from the front, and if you cant see her dishing (winging to the inside) then look for her knees moving outwards when she lifts them. This indicated that she is dishing, but I wouldn't let that put you off buying her, just use boots - open front jumping boots with a hard shell are often good in these cases. I wouldn't use bell boots though, as if shes going to hit her own leg, then the bell boot will add extra bulk and she may trip. :)