I agree with RTT, I would prefer if prizes costed 6* or 7*. I get the idea behind prizes being 0$, it makes it easier to understand the rules, because you say, hey, surely Donald isn't going to let me buy Trusty Steed for 0$, let me have a look see at this italicized text.
But it produces counterintuitive and less interesting results when other cards try to interact with that cost. The choice of whether to Salvage your Followers isn't difficult at all. Your opponent's choice of whether he should try to use Saboteur on your Followers or invest in Horse Traders instead is not an interesting choice. The Swindler interaction that is the topic of this thread is nice in that it gives you a response to the ugly, asymmetric aspect of prizes, but most other interactions make me wish it wasn't 0*. It'd be nice if I could try to make a comeback against someone who took the two strongest prizes by using Apprentice on a Bag of Gold or something, but I can't.