Materials are the fastest selling thing on the market right now. They require little to no re-posting. Which is pretty valuable to me now because my nose is in other markets. IE: Guild specialing darkmoon trinkets.
There's some money to be made in the mastery enchant market, but it takes infinitely more market management than just getting 2 crystals and putting them up at 500g ea per day.
Going through the trouble to fight the over-abundant undercutters on hyjals market (in comparison to other servers) is just not worth the 200-300g extra you'd make in the process. **Unless 200-300g is a lot to you**
Time spent elsewhere, like watching a sniper scan, or flipping darkmoon trinkets/boe epics is more valuable.