I learned on Woolease. I think some of them carry Patons 100% wool now too.
Another thing to experiment with is your needles. Some people prefer some kinds over the other, and some materials (wood, metal, plastic, etc) work better with some yarns. I prefer metal, but wood if I'm working on dpns so the yard doesn't fly off.
I was also told, and I'm not sure if it's true, that 100% cotton is hard for a beginner because it has no give.