Go to your local shop that is a Parts Unlimited dealer and order a set of AMS Swamp Fox tires. They are about the cheapest ATV tire that is actually a good tire. Sold alot of them at the shop I used to work at.
Austin's ATV in Evarts, KY. He's hard to get on the phone but he's the cheapest I've seen. 606-837-2002. He will ship them to your door and you'll have them in less than a week.