Baron

Description: +1 Buy.  You may discard an Estate card.  If you do, +4 Coins.  Otherwise, gain an Estate card.
Type: Action
Cost: 4
Set: Intrigue

I was a little skeptical on the usefulness of this card at first, but it can prove to be pretty useful if your strategy revolves around low coin costing cards.  If you can combo this with like the garden card, then it turns out to be pretty darn good because it keeps giving you free estates if you need it.