Pattern: Blue Linen Vest

About 7s 0c on Beta · Horde (2 hours ago), 8s 0c on Beta · Horde (19 hours ago), and 19s 0c on Beta · Alliance (21 hours ago), from player scans. A vendor pays 50c, so the auction house pays 13.3× 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 6s 65c there, against 50c at a vendor.