I just realized that with both a +1 buy and a "when you buy this, play it", then if you get 5 cost reduction out, you can instantly buy out this whole pile. Maybe that's not a problem though; it's not easy to do.
But then again, if you do do it, you will gain 10 Emporiums, plus 10 of any other card costing up to $5. Like 5 Duchies. While your opponents cause the game to end by draining a 3rd pile, unless they take Coppers.