As others have said, slicks should last a long time on 12-13 second car. To help them last, keep them out of the sun as much as possible, don't store them outside between races. Dress the sidewalls with Armor-all occasionally so they don't dry out. Well cared for they should last a full season at least, maybe two. I found the serious 10.5 inch tire racers to be a good source for used tires as the others have said.

Pat