Oiled Blunderbuss

About 18s 0c on Beta · Alliance (22 minutes ago) and 20s 0c on Beta · Horde (6 hours ago), from player scans. A vendor pays 11s 73c, so the auction house pays 1.5× 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 17s 10c there, against 11s 73c at a vendor.