Oh, it was not sticker shock for me, she was very upfront about her fees when I first contacted her. She did a very good job, I felt it was worth it. I know Petco also does obedience classes, I think (back then, anyway) it was also like $90 - $100, for 6 one-hour classes, but obviously there were other dogs there, and you did not get the one-on-one time. And she addressed any issues very well. I felt the dog benefitted more from private lessons.
I think (I hope) I tipped her, but I think it was only like $5 or $10, not my usual 20%. Looking back, I would say she was worth the 20%. Our dog has/had a pretty independent streak, and she helped teach us how to reign him in. I think he (we) definitely benefitted from the one-on-one lessons.