Here is what I use for foundation sewing: I often buy bedskirts at thrift stores to recycle into fabric. When I have removed the skirting part, I use the platform section, which is usually thin fabric, for my foundations. This is like getting free fabric to use as it's the 100% cotton bedskirt that I am really after. A King bedskirt is usually $3.99 and I buy on senior discount day so then it's $2.99. I get yards of fabric that is perfect for kaleidascopes or any other purpose, as it is in long lengths, and the white platform top as a bonus!