Just to revive this. I bought ONE tire yesterday. Replacing a Sams Club BFG tire with the same tire. Back on 12/11/05 a set of four, out the door was $270.50. So that works out to be $67.63/tire including all the charges and taxes. The tires themselves were $52.04 each before taxes and fees.
Yesterday, same tire, about 4 years and 66K miles later is $80.33 out the door.
The installation/road hazard/lifetime rotation went from $9.00/tire to $15 and the tire went from $52.04 to $58.26
So from my very limited perspective, I don't think tires themselves have gone up all that much. Half of the increase was the price of the tire, the other half was the increased cost of install.
I had to buy only one because I had replaced a tire in January due to road damage and the road hazard helped. I sure got more than $15 in value. (Actually, I paid $9 on that tire.) I picked the worst of the three oldest and had it replaced. Technically it could have gone to 70K, but I wanted at least two newer tires on there before winter.
The previous replacement tire went on the rear in January because I wanted to minimize the wear and wear out my older tires faster.
Yesterday, the fronts went to the rear and the two newer tires went up front. I still have about 4/32nds on the tires rotated to the rear. Not bad for a 70K rated tire. I'll likely get the full 70K out of half the tires. Not bad at all for a FWD car that is not driven gently.
I like this Sams Club as they don't give you the line about new tires on the rear. They realize that you are eventually going to rotate them anyway.
So I'll see if I can go another 10K miles as is, and then replace the rear tires. If it gets too squirrely in the rain or snow, I'll replace the other two that are following along.
Newer cars are taking larger sizes which is driving the prices up. I think tires have gone up due to higher oil prices, etc. But the 11.9% increase I observed in the same tire over 4 years isn't too outrageous. It works out to be about 2.9% increase annually, or right in line with inflation.