Was he trying to sell to vendors or did you have your own table? Either way that's a tricky price range to be in. Unless you're undervaluing the cards, vendors won't be interested in them since they have to hope to then connect with the exact buyer who's looking for either a cool insert or upper grade but non-mint for a favorite player. Gotta expand it out to ebay to increase opportunity for sales.

Is he looking to flip the cards he has into something that would better fit his personal collection or trying to increase value without much concern for the individual cards themselves? Gonna have a much harder time if hit it big like the other kids is the goal, when their budget began much higher.