Clay
Action-Victory-Treasure
Cost: $6
Worth 3 VP
(EDIT: Interaction with Kiln. It doesn't innately do anything when played, though it would interact interestingly with Ways and tokens. Arguably, would be a pretty fun 2nd half of a split pile with Kiln, though as a split pile, it could run out before you even got a chance to Kiln yours. Perhaps 5 Kiln/10 Clay would be fair here. If it's not in a split pile, it would be completely dead on most boards, needing a reference to card types at the very least, or you could use it as a last resort backup Duchy.)