I bought through them last year and it worked out on continentals. The prices were jacked up per tire but still ended up cheaper than buying 4 elsewhere, and I submitted to continental for a rebate too. That was a bit of a hassle due to the way Chrysler billed the tires out, but I just explained to 2 or 3 people that I did in fact buy 4 and eventually they approved my rebate.I just ran comparisons on my higher end tires, and as predicted and from my past experience the "buy 3 get 1 free" is a gimmick. They just increase the prices of tires so it is nearly the same as just going to any reputable shop without gimmicks.
Tire prices fluctuate though, so I’m sure it’s something that has to be checked currently and not just relied on someone else’s past experience.