Unless "old" means the early early issues, they're not going to fetch anything more than 10 bucks each.
thats still pretty good considering they cost probably between $.50-$3 to buy.
i collected a bunch of things as a kid: beanie babies, pogs, pokemon cards, magic cards, baseball cards, etc.
nowadays i read comics but i only keep up with a few series (Batman, DMZ) and the occasional one-shot or trade paperback so not really AVID COLLECTOR