Yard sales or flea markets can often be successful for this sort of thing….I once sold a Star Wars hologram card for $30 at a flea market. Remember, kids who collect this type of thing will be coming along with their parents, and if they’re collectors as well, may be able to convince their parents to buy them something. Also, kids today have an alarming amount of money to spend of their own.
All this being said, you will most likely not unload these cards in bulk in the above type of setting, but if you want to get the maximum amount of money out of your collection, I would try this option. Also, get some binders and some clear sheets that the cards go in to put in the binders. People are more likely to buy them if you have them neatly displayed and organized, and if they can flip through them they will find it easier to locate what you are looking for…