If your intent on getting to lvl80, save yourself a lot of cash, especially at the later lvl’s by not spending oodles of money in AH on equipment. As soon as you arrive in Northrend, the first series of quests are all about replacing your equipment; that means all the money that you spent on those blue and purple items are now as good as grey! lol
Much better to use equipment found in quests and dungeons.
P.s.: remember, as soon as you start raiding, you will need different equipment as well!
P.p.s.: I am a weaponsmith 🙂