If you have a socket wrench, a 15mm socket(might be 13mm...), a T50 torx bit and 15 minutes to spend, you'd be crazy to pay that much. It'* VERY easy. Cost for the two belts shouldn't exceed $50-60 total.
I had already decided I was going to do it myself. It took me about 10 minutes last time to replace the belt(*) on my GMC truck. I just needed a chuckle on what the friggin' dealer was going to charge me!