As Dan said, if they are HSS, I would say it is a fairly good deal. What length are the tools ?
It seems you'd be getting 10 pieces, although I can't really make out the bottom 4 which look like small gouges, etc. or carving tools.
Forgetting the bottom 4, for the top six at $100, that's only $16 each.
The bit of rust is a little unsightly but otherwise won't affect their working, and you can make a fair job of cleaning it off.