Whispering Vest

About 29s 0c on Beta · Alliance (3 hours ago) and 20s 0c on Beta · Horde (1 day ago), from player scans. A vendor pays 5s 47c, so the auction house pays 5× 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 27s 55c there, against 5s 47c at a vendor.