I don't know about you but there is just something gratifying about crafting items. And who is not too say how high you can go and craft some cool items that might sell for a lot more on the auction house - it might end up being worth the investment.
Maybe just for Legendaries/Sets, though, unless you craft something especially good or you snag a sucker.

Yeah... don't buy stuff on the AH. At level 19 I decided to check it out and ended up replacing every item I had for like 10k gold. My Barbarian now has something like 3x the HP, 4x the Strength, 2x the armor rating, +15% attack speed, and a bunch of other modifiers. I'm pretty much invincible now and any loot I find in game is completely worthless to me.
Definitely going to avoid using the AH going forward. Kills a big part of the fun of the game.
You could always try selling that stuff back for a bit more bread than you bought it for
