[size=12]In my own opinion, that's pretty good, provided that the skillet isn't warped and doesn't have any other problems. They list for $50 in the blue book, in perfect condition.
In your first picture, the one looking down on the inside of the skillet, there looks to be a little irregularity along the rim from about 9:00 to 12:30 or so. It looks to be on the top of the lift assist tab, too. Is that pitting, or is it just crud that will clean off? If it's pitting, then that might be why the skillet was priced lower than list. If it's just crud, and there aren't any other issues with the piece, then you got a real nice price. [/size]