Anti-Venom

About 28c on Beta · Horde (5 hours ago), 28c on Beta · Horde (23 hours ago), and 28c on Beta · Alliance (1 day ago), from player scans. A vendor pays 28c, so the auction house pays 1× more.

1 recipe: Toxin Study.

No. It is in Classic Era too, with the same item level, vendor price and stack size.

Sell it to a vendor. A stack of 20 brings 5s 60c there — more than the auction house nets after its 5% cut.