I just sold about 40 Firecracker bombs via the AH, about 1000 crowns a piece. I used up all my mist tanks for crafting (to not touch too much of my CE), but that really was worth it. Sometimes the bombs sold faster than I could post new ones. Also, the first spare Firecracker recipe I had was worth 5000 crowns to someone, I'm expecting to get even more for the second. And all this for a one star bomb.
Crazy, I tell you!
Why didn't I think of that?! I just bought the bomb a few days before the achievement release from a vendor for 3000, never occurred to me to make money off that achievement!