I went to my (now closed :pout:) LYS to learn to knit and I think it was $35 for two one hour sessions. I had missed signups for the regular class, so the owner taught me herself (I was a class of one.)
I'm all about supporting local businesses, so I bought my needles, yarn, and even the Vogue Knitting book from her. I have no idea if she required it or not -- it just seemed to me the best thing to do.
As for your question, I have no idea. I like having someone looking over my shoulder and saying, "Oh, don't put the needle into that loop, you want this one" or "Oops, you forgot to move the working thread" before I start the next stitch.
Learning by myself means it would take me longer to notice my mistakes and probably longer to unlearn them. :roflhard:
I'm not sure what I would be willing to pay for more than basic lessons -- it would depend on what it is. (I almost paid $45 for sock lessons until I figured out the three dates were not available classes, but that the class was three sessions. Then I couldn't do it because of the class times.)
I would not pay for an online class because part of what I pay for is the live person watching me and noticing my mistakes before I do. :doh: