Huge Venom Sac

About 23s 0c on Beta · Alliance (33 minutes ago), 23s 99c on Beta · Horde (6 hours ago), and 24s 0c on Beta · Horde (24 hours ago), from player scans. A vendor pays 15s 0c, so the auction house pays 1.5× more.

1 recipe: Powerful Anti-Venom.

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

Sell it on the auction house. After the 5% cut a stack of 5 brings about 1g 9s there, against 75s 0c at a vendor.