Dalaran Wizard's Robe

About 75s 0c on Beta · Alliance (4 hours ago), 3s 0c on Beta · Horde (10 hours ago), and 3s 0c on Beta · Horde (1 day ago), from player scans. A vendor pays 2s 57c, so the auction house pays 27.7× more.

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 1 brings about 71s 25c there, against 2s 57c at a vendor.