Don't bother buying the easiest stuff. A few runs of VC, SM, etc will yield the cloth you need for linen, wool, and silk. (Hit up SFK for possible twink drops and wool.) Probably save you a few hundred cold, but cost you about 3 hours.
After that - buy the mage weave, rune cloth, and netherweave -
Like it was said above - It's really server to server.
On my server NW was selling for about 6-9G per stack.