Get that wheel straightened, or replace it. Even if you only got three good wheels for $100, that's a great deal. Just because it balances, doesn't make it run true. You can high speed balance a square or an oval just as easily as a circle.
When I bought a set of used SVT wheels, they looked fine until I mounted them on a hub and measured the runout at the bead. I ended up paying $150 to get all four trued up. (many shops charge $150 per wheel!)
I just bent one of them again on a big pothole yesterday, so I'll be going back to the wheel repair guy Tuesday (less busy time and day = cheaper labor)