I get all my fusible fleece from WalMart. I like their's much better than what I get from Joann's, it is heavier and cheaper. Interfacing is something that adds substance to fabric. It can be very light to very heavy depending on what you are using it for. Fusible web is used to fuse 2 pieces of fabric together (like applique). There isn't much use for web in purse making. My usual needs are- Medium wt. interfacing for pockets, fusible fleece for exterior pieces and sometimes Decor Bond to stiffen lining if I want the purse to have more structure.