DAVE: My avid baseball card collecting days were primarily in middle school, I guess, before I discovered girls. I kept a record of all the cards that I paid money for from mail-order catalogs or a little card shop that used to exist in a place that I walk by everyday when I'm walking dogs in my old neighborhood. In come cases, the cards have definitely increased in value. However, it's interesting how many cards from the years 1966-1975 that I bought for around $5 that are only worth about that much now. So, they've actually LOST value in the 30 years since I bought them. And all those "whole sets" of 1980s Topps cards that I bought back then: essentially worthless.
JIM: Yeah, I had friends who used to buy the whole sets. so many people back then started buying them and there were so many cards produced, that's why they have no value. Because everyone has them. I had friends who used to root through large bins of the Topps 3-packs. They sold them as three packs of cards in one, and you could see the top and bottom card of each pack. So guys used to go through them all to see if they could find packs that they knew had particular cards. I don't know why I remember this, but I remember that any pack containing Mark McGwire's rookie card in it seemed to be particularly in demand and if one could be found, the pack would never be opened because it was deemed to be worth more unopened, even though there was no way of knowing what other cards might be in it. Seemed kind of stupid to me.
Then again, I had my comic books. And the same thing has happened there too.