That's Robert Jennings you're buying from, the guy who ran
Massconfusion 1984. Whilst this module was written by Duncan Davenport, if you buy any of the modules Robert wrote, you can always get him to sign them.
Cost wise, I've seen these go mostly at the $15 mark, but they go up and down all the time, and the seller seems to have boxloads of them. The non-D&D modules are often harder to find, and Dungeon of Dr Demento is stupidly rare. I've only ever seen two copies of that one in five years.
Quality is on the whole quite good. I enjoyed Dragonrunners of Kola, and remember thinking Werewolf Country would be interesting to
DM. Didn't like Lady Eileen's Castle much, and the Dr. Demento tourneys were a little too off the wall for me. On the whole, well worth investing in.
This week I've been mostly eating . . . The white ones with the little red flecks in them.