The Amazing Spider-Man and Cap'n Crunch from 1987
Old books are more expensive based on rarity and desire. If you just want to the story from old comics, most of those things are reprinted, not sure how many collectors sell with their emotions attached, but I can only speak for myself, that if I love something so much, it isn't for sale. I think the best thing about collecting is there is at least in the comic world there Overstreet guides, then Wizard magazine, and now there are a few sources like ComicsPriceGuide among others, that let you get a fair market value for any given book, that way as a buyer or seller you can at least have an agreed upon number to start at. Good luck at starting a collection, jump in one day with just stuff you really love and it'll pay off in that regard, don't go just for what is the hot book, as that will always be the most expensive.