I am guessing the internet has eliminated the thing most collected from this group. I collect memories. Pictures of places I have visited, ticket stubs from games and concerts I went to.
I used to do baseball cards and marbles as a kid. Now it's random pint glasses from bars or breweries and you may laugh, but I collect hotel room key cards. I store them in cigar boxes.......
I have boxes and boxes and boxes of baseball, basketball and football cards. Many valuable cards too. I spent every I earned for years when I was a kid on amassing this collection. When I got into high school I stopped collecting. Sometimes I think about getting back into it.
Try the thrift stores. I collect classic movies on VHS. And they usually go for 50 cents at most if not all these stores. You'd be surprised at some of the great movies you will find that way. Although, I know most people look down on VHS nowadays, and most homes don't have (working) VCR's. I also collect basketball cards and video games.
I wonder how many of you on here collect days of being a virgin or not having sex. Gotta' be some huge collections of that on here.
I had fun calling a bunch those while you and I were tooling down the road to the beach the other day. I'm such a cad.