I haven't ordered anything yet, but I have been shopping around for a better price. The difference in price from one seller to another is astounding. The prices below include mounting and balancing. For online sellers, I've added extra for mounting and balancing. Also, sales tax is included where applicable.
Sears (with promo code): $666.27
Discount Tire Direct: $756.00 (I asked for a price match and they asked me to give them a call. I'll follow up with results when I call.)
Local Tire Place #1 (family price): $709.14
Local Tire Place #2: $801.36 (This is the original place I was going to purchase them.)
Local Dealership (Not FoMoCo): $896.48
As you can see, there is a significant difference from the least to most expensive.
EDIT: I just wanted to follow up regarding Discount Tire Direct. I just hung up the phone and that place is phenomenal! They only required that I submit a link to the tire, which shows the lower price and they were actually able to beat the price. The final price, shipping included, was $596.00 for four General G-Max AS-03 tires. That is unheard of for a 245/45R20 brand name tire. As long as the rest of the transaction goes this smoothly, I don't see myself ever buying from a different seller.