Buying new tires for your cub cadet lawn tractor doesn't have to break the bank. You will certainly spend more if you want a set of OEM tires that say "Cub Cadet" on the side. Most cub cadet models use tires manufactured by the Carlisle Tire Company. You can usually buy the exact same tire, minus the branding, for much less.
Other manufacturers also make cub cadet tires. Have your model number and tires sizes handy when shopping as some models, like the Cub Cadet 1554 have different size tires for their SLT or GT models.