I realize that not all areas are equal, but I've been buying most of my fabrics while thrift/estate shopping for years now. I'm paying typically $1-2 per yard or buying in large lots. No, you can't just go out and get the perfect fabric when you want it. You have to collect fabric and know how to use it. Fortunately for me, I work in a scrappy style and I don't try to copy other projects. Unfortunately, it means you have to store fabric for when you might use it and that builds up stash.
My biggest issue is backs, I'm pretty much out of anything in stash that is 6 yards or so. I've developed ideas for using coordinating/contrasting 3 yard pieces. I try to spend $20 or less on backs and that's pretty challenging. One thing is the extra wide fabrics are typically not on sale with the other quilting fabrics at Joann and are something that you can actually use the 50% off coupon.
Edit/Forgot -- one place I have gotten large amounts of fabric for cheap is on Craig's List or an Auction site I like. Nope, just like the thrift stores it isn't new stuff but it is unused. This auction went higher than I would pay (I'm cheap) but is an example of being able to get a lot for just a couple yards of new.
https://maxsold.maxsold.com/auction/...ters-b-3752983