ccbear. You will usually find the fusible fleece in the same place that you find the rolls of batting , wonder under, and the like. When I have bought it, it has always come off of a bolt.
I use thin polyester fleece everywhere that I can get away with. Like the handles. the inside pockets, and outside pocket. I use the fusible fleece for the body of the purse and the inside lining. It gives it a certain stiffness, so that it will sit up. But, the fusible fleece is a bit pricey, so try to use a coupon or watch for a sale if you can.