Warrior's Girdle

About 5s 0c on Beta · Horde (9 hours ago) and 1s 0c on Beta · Alliance (12 hours ago), from player scans. A vendor pays 23c, so the auction house pays 20.7× 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 4s 75c there, against 23c at a vendor.