I have a card that I think is a $5, but what do you think?
Hunter
$? - Action
+1 Action
Discard a card.
Do this twice: Look at the top card of your deck and choose one: Put it in your hand; or discard it and +1 Card.
If you do the math, you will see that you wind up with exactly the number of cards and actions you started with. So it's a cantrip, I guess you'd say. What it offers, however, is a way to improve the current hand. So it's like a Cellar that doesn't shrink your hand-size (which is a pretty big deal). Or a Spice Merchant that doesn't trash? But the degree of hand-improvement tends to be very good.
Basically, you get rid of two cards -- the weakest card in your hand, and the Hunter itself -- and replace each with a card that is probably better than the average card in your deck. I've not done nearly enough testing with this yet, but I have played it in a real 2p game, and it seemed to be a pretty good card.
The inspiration for this came from the dealing rules for 2-player Spades: in drawing his hand, each player looks at the next card in the deck and decides whether to keep it and throw the next one away, or throw it away and take the next one. This is less sure than simply looking at the next two cards and picking the best one, but it's a whole lot better than just taking the next card, whatever it may be (as Cellar requires). Anyway, I really liked that particular game mechanic and thought I'd like to make a Dominion card that uses it.
Thing is, it probably needs to be done twice to be interesting. (I suppose you could use it once in a $4 Village-with-a-bonus, too). But then you'd get a strictly-superior Laboratory, so I weakened the card by mandating a discard at the outset. That's a pretty severe penalty, maybe.
Anyway, I'll be doing more testing soon, but I thought I'd solicit opinions here, too.
Anyway, thoughts?