Harbor freight don't sell them any more. Best bet is to try all the stores in your area. If you have no luck the I know there is a supplier on eBay all the time that has them in stock all the time. He charges a little more then harbor freight, but they are still out there for a little while longer. You may even be able to find an individual seller on eBay as well with a preddy for sale.
99CC OHV Horizontal engine