So, I submitted this to rinkworks' contest, and a lot of you (rightly) pointed out its flaws. It's very swingy. So in an attempt to ameliorate that, here's a couple different things to try:
Jeweler
Action - $5
+1 Action
+1 Buy
While this is in play, whenever you play an Action, +$1.
(This overcomes the "needs a Village" problem, but still has the KC "here, have all the coins ever" problem.)
OR
+1 Buy
+$1 per Action you have in play.
(This might be too similar to Bank.)
OR
+1 Action
+1 Buy
Name a card you have not already named with Jewelers this turn. If it is a Victory card, it acquires the type "Treasure" for the rest of your turn. When you play this card, +$1.
(This might just be too weird.)