That Monte still has like 6 days to go...I would scoop it up quick if I saw one for 20 some dollars...I see the 80's MC's go for up to 50$ depending on the color and the quality of the plastic.
The 71 can be priced as high as $250 at some shows. Every dealer I have talked to claims that their promos are the "rare" color. I guess you have to do some research to see which ones are really rare...That yellow is friggin bright!!!! lol