well, I have been running as a few of my friends, Carlisle Guard Dog HD tires, there fairly aggressive and been very durable in roots and broken concrete and likes, no flats or damaged sidewalls to date!
but they do tear up grass/lawns and NOT the best in snow, but no standard skid steer tire is very good in snow/ice, rubber is too hard and not enough edges and snipes , but I DO plow with them, they just spin a lot, HAHA
and there NOT cheap tires, but they are quality tires IMO
if your just looking for cheap NEW general tires, with no real needs for "X" type of tire thread or side wall,
I would suggest checking out your local Craigslist adds, I see many folks selling cheaper skid steer tires , many times with wheels included in package deals,,
some also have betterands and better tires too(its how I got my last set)
that OR I would check out EBay and or face book market place, they seem to have tons of folks selling things these days from cheap off brand names to name brands(how ever be ware lots of counterfeit stuff last few yrs on both ebay/facebook market place)
but many times cheaper than local tire shops sadly! , or thats how it is in my area!