IMHO, the ones that are worth anything are the 1/64 FEP run cars. All the rest are pretty easy to obtain when looking for them. Even the limited Toy Fair Show pieces and the Chase Raw pieces are easy to locate from time to time. Now the 1/18 scale hold a different value as many like to repaint them, then flip them for a nice profit. You can try here to sell what you have or try eBay.