My first purse I followed the instructions to the letter including using whatever was called for.
Now I use regular fleece, remnants if I can find them. I attach the front & back and the linings using a zig zag stitch around the outer edges (here a serger would work perfectly). Then I quilt it. My way makes more work, but I find it doesn't take me as long anymore. Cutting out all the fabric, fleece and interfacing is what takes time. I also use craft iron-on interfacing for the handles. Using fleece makes them too stiff.
I also use two different machines to make my purses, a Singer 500A 'Rocketeer' for the zig zag stitches and then my Singer 301 which sews through all the layers like a hot knife cutting through butter. Having a great machine makes a big difference also. Love my Singers...............
Blessings,
Sandi