Does anyone know where to sell trading cards?  

Hi there. I'd say a good place to start would be e-bay but then, considering that your item is of special interest of a specific group, it would be good to also consider offering your items for sale on forums and communities who share the same interest in trading cards. For example, I have sold some memorabilia and CDs of a Japanese pop group that I'm currently interested in through the Live Journal community specifically created for fans of such group. My sister and her boyfriend also sell action figures through e-bay and a special interest forum. I guess it's best to look around the net for such groups/communities/forums. Good luck.

Have you tried on eBay? I have been selling some clothes on this site and the respond turn out quite well. I managed to get some extra pocket money from there. :)

Alot of people have suggested Ebay or an online auction site - and that is good advice. Alternatively you could try going to a comic fair or someting like that and offering them for sale?