When my and wife looked at the Optima, the sales guy (who also owns one) said they sell them right at the dealership, so I would start there. They retail for $30 and he told us it's not worth it in his opinion. He had one, but it kept falling off and didn't hold the drinks any more securely than just on the shell directly. That was his opinion. If it's cheaper on Ebay, I think it's nice to have.