Elixir of Agility

About 15s 75c on Beta · Horde (5 hours ago), 18s 75c on Beta · Horde (22 hours ago), and 27s 0c on Beta · Alliance (24 hours ago), from player scans. A vendor pays 2s 0c, so the auction house pays 7.5× more.

1 recipe: Quickdraw Quiver.

It exists in Classic Era too, but with different numbers there.

Sell it on the auction house. After the 5% cut a stack of 20 brings about 2g 99s there, against 40s 0c at a vendor.