I would see this as a big Big Money enabler. Which I actually like a lot, I think the pendulum has swung too far the other way nowadays.
I think you misprinted though? Like, surely your intent is for you to gain a Copper when you buy Peddler for 0$.
This guy will basically reward decks that go light on actions, even Big Money is trying to play 1 action per turn, so the lighter the better, 6$ Peddling is the best and 4$ Peddling is second best. It also gives non-drawing Big Money some much needed love. (Poor Merchant ship)
EDIT: I read your post, it seems like you intended for 0$ Border Peddlers to have no baggage. I think that's a really bad idea. Peddler is already a pretty swingy card because lining up your actions and buys can get you several early, and then those Peddlers help you get more. You'd be making this even swingier if the guy who gets the cost down to 2$ can't buy it at all, and then the guy who gets it down to 0$ gets to buy it in optimal conditions.