You should get to know what wonderful fabric feels like, so you know the choice you're making when you decide to buy less expensive stuff. I always head straight for the 'sale' table or remnant room in a good quilt store, to see if I can find what I need there. I don't buy online, because I hate paying shipping charges, but I know that many on QB find great fabric for lower prices on some of the online sites.
If you go with less expensive fabric, I would advise pre-washing. I have had some cheap fabric shrink on me on the ironing board! Very painful.....