Burlmart - Glad you called "discount tire" and learned that they only sell passenger car tires. I suspected that based on the pricing. You saved me a phone call.
Based on the pictures you posted in
Judgment of Pictures of Sidewalls of 6.5 yr Tires, I would be looking for new front tires. I might postpone the rears for next year. That is a decision only you should make for yourself.
I have always had a little different opinion on tire replacement. I have frequently purchased new tires per axle versus entire vehicle. I always seemed to be too poor to write that bigger check for all four tires on my cars when I was younger.
I have been more than pleased with the "Generals" that came with mine. Have had zero problems, ride seems to be smooth when the air pressure is set for the load being carried, seem to be quiet, and had good traction when driving in the Colorado mountains during a snow storm. The big semi's were pulled over for chaining up and we merely drove around them.
Might use this website as a price check point -
TireRack.COM.