It sounds like everyone is using mostly from their stash - congrats!!
I bought a half yard bundle from Blueprint of batiks for my MIL bargello quilt so that purchase doesn't really count and I'm adding from my stash to have enough fabrics. So I bought 5 yards and I'll use that much from stash. I also think the backing will come from stash as I have a piece big enough to coordinate well with it. That quilt is still in the thinking and gathering stage.
I am currently quilting my scrappy Irish Chain. This one is an oversized throw so would say 4 yards of fabric for the backing and binding and another yard or so for the background in the top.