I do the Salvation Army/Goodwill for the cotton dresses, etc. I do the estate sales for sheets, notions, etc. I recently bought some flat sheets, in the package, for $2.00 each.
My newest kick is old buttons- got a bunch for $1.00 that had buttons, sewing tape, bias tape, snaps, etc. I had fun just looking at my "loot".
I found a gorgeous cotton jumper for $1.99- the pattern caught my eye- but it's in my size and I'm seriously thinking of wearing it. But it is sooo pretty- I really want to cut it up. Decisions, decisions.
I also did the same with a bolt of batting. I figure I know I will use it, so the cost saving of $3 or $4 a yard by buying in bulk is worth it. And it feels neat to hug a bolt of batting when you are getting ready to sandwich a quilt.