Discount Tire is running a promotion on 11/23 and 11/24 where they will take $100 off any set of 4 tires.  From talking to a few people who took advantage of the last time they had this promotion I could see that people were very pleased with this website and with the quality and price of the tires they got…

The website is here http://www.discounttiredirect.com

Shipping is FREE from this site, and you may be able to find rebates on certain brands from the manufacturers (the last time they ran this promotion a friend got a set of 4 Michelin tires for $310, less $100 discount, free shipping, and then he found a $50 and a $40 rebate from Michelin, so in the end he got 4 great tires for $120 on his doorstep).

I do not believe you need a coupon code or anything, you just need to purchase on the specified days (from what I gather).  Enjoy the tires!