Enchanting is a really expensive profession -if- you are buying green items off the AH to disenchant.
However, enchanting plus tailoring is a pretty powerful combination. You can farm instances very easily with these two, assuming you've got a character of sufficient level. Take the green items and disenchant 'em; take the various cloth drops, make them into green items, and disenchant -them-. And those lovely bind-on-pickup blues that would have been really neat if you were twenty levels lower? Disenchant them too! Cash drops from the mobs will cover your incidental expenses.
A few runs through the Deadmines should net you sufficient materials to level both tailoring and enchanting well past 100; at that point, it's time to go on to tougher instances.
Fact is, most of the professions need a gathering skill and a production skill to work properly; it's tough to be a skinner without leatherworking, and tough to be a leatherworker without skinning. So if you're going to master Enchanting, you need to kiss off mining, alchemy, leatherworking, and the like. Moreover, Enchanting is a -terrible- skill to put on an alt, at least for the Alliance, because the master trainer is in Uldaman! Not a trip you want to make often with a low-level character...
On the other hand, you don't need a gathering skill with Tailoring, just the frequent killing of humanoids... something everybody does regularly anyway. ;p