I followed a guide to get from 1-300 and it was excellent, it won't be expensive you if farm the cloth yourself. No idea how much it would be if you bought it all, it would depend on your servers prices. Once you hit 300 and get Outlands patterns the cost goes up exponentially, especially post 350. But if you have a lot of gold or friends to farm cloth for you it wouldn't be so bad.
This is the guide I followed to get to 300: http://www.xs4all.nl/~brt/wow/guides/skilluptailoring.html