I bought a featherweight machine I use for straight sewing classes. For classes where I need a machine that does specialty stitches I bought a little "Audry" by Baby Lock. It only weighs about 12-13 lbs and comes in a fabric case that really doesn't add much weight. I can easily carry and lift it when I need to for a class. Before those two purchases I wasn't taking classes due to the weight of my good machine.
Good luck
Kat