#420RazeIt
Raze is fucking great, particularly if you can remove the opportunity cost of buying it.
The first thing to keep in mind is that Raze is, at worst, a one-shot cantrip that discards a card you didn't want. So it's hard to overbuy them, and there's almost no reason not to get one on $2 since you can just trash it anyway. In so many games I've hit $3 when I needed to hit $4, but didn't want another Silver, so I bought a second, or third, or fourth Raze. Even if it just trashes itself right away, it's usually better than nothing, and if you knock one Copper out of your deck with it beforehand, good enough for me.
A Raze play on an Estate in the second shuffle guarantees whatever else you bought will not miss the shuffle. This is huge.
Raze is good enough that I've used it as the only trasher on a board to thin my deck out, but obviously it works best as the "second trasher" that eventually gets rid of your trash card and then itself.