Check the "going value" for those games here on Pinside. If the condition is better than most, it is probably toward the high end of the range and vice versa for a poor condition game. Also, sell at a price that is comfortable with you. Too many are looking for a lo-ball deal only to eventually resell at a higher price. Those people are disgusting for this hobby and they are everywhere. Also, try posting in the Pinball For Sale group on Facebook. That seems to be a popular site, certainly better than CL. The lo-ballers scour CL.