In our local thrift stores, if you watch their specials, end of season bag sales, etc. you can find high end clothing. Shirts that retail for $45 or more usually have quite good fabrics. Just read those tags. I also like to use woolens for applique, penny rugs and (bucket list) someday a braided or hooked rug. I have found Army blankets and other woolen blankets and older men's overcoats at thrifts and flea markets. It's remarkable how cheap good wool can be when there's a hole in it. 8-)
Today at the thrift store I found a garbage bag of partially deconstructed heavy woolen clothing for....(drum roll).... $2. On my way to the cash register I dipped my free hand into a bin of sewing notions and came up with........a baggie of six dozen 6 1/2 inch squares with primitive stars appliqued on each one and every one is different and I know just what I want to do with 'em.