I make loads of quilts per year... probably upwards of 40... and I'm not rich. Most of the ones I make are throw sized, to give to a charity. I buy for my stash when I can find good fabric for $5 or $6 a yard, or less. Mostly online auctions, clearance sales, and stash reduction sales by individuals. And I have a ton of scraps that I have cut into precuts.
I buy batting by the big roll from Marshall's Dry Goods. It's not expensive.
Backings will be pieced or may be a nice cotton sheet. I'm always on the hunt for those.
I do my own quilting. The note on my Juki sitdown longarm is $94 per month.