I'm not sure of any specific sites, i did a search for tire rotation coupons and a bunch came up, alot of local business coupons though. Maybe you could do a serach for tire rotation coupons in " your area" . Good Luck finding something, hopefully someone might have something great for you!
BTW..I have a 2003 Honda Accord! I love it! I'm on warranty also but now Im nervous, they never told me I had to do oil changes and what not at the actual honda certifed shop for it to be good. Hmmm I guess I better check into that!