Welcome to the board Cody! Nah, you're not crazy. You might have a tougher time finding a 71 Cuda for that price...71 Challenger should be no problem. Most people on the board check out eBay (I've bought 2 cars off there with NO problems at all), but there are a lot of other places on the web to check out. If I see any, I'll post here.
Again, welcome!