It is actually called "stringhalt" and here is some more info on it. The Horse | What Is Stringhalt?
It sounds like what you want to use this horse for would not be adversely affected by roaring, but always ALWAYS have a horse vet checked before purchase, as there is a gradation of seriousness with both of these conditions. If the horse is both a roarer and has stringhalt (kind of unclear on your questions, sorry!) I would pass, especially in this market. You can find some pretty great horses in your price range without any soundness issues at all. Best of luck to you!