Heavy Armor Kit

About 38s 60c on Beta · Alliance (6 minutes ago), 29s 99c on Beta · Horde (6 hours ago), and 40s 0c on Beta · Horde (1 day ago), from player scans. A vendor pays 6s 50c, so the auction house pays 5.6× more.

2 recipes: Forceful Heavy Armor Kit and Mystic Heavy Armor Kit.

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 10 brings about 3g 66s there, against 65s 0c at a vendor.