Tim
I'm not sure what size you are looking for other than 22.5. For Michelin 235/80R-22.5 tires (which is the size on my Challenger) you would be looking at about 450.00 per tire not including taxes, mounting or balancing.
With that said, a fellow FMCA member I rally with from time to time used the FMCA Michelin Tire Advantage program this spring and saved about 150.00 on each tire. He replaced all 8 on a Thor Mandalay with tag axle. According to him, through the program the tire dealer ensured all 8 tires were manufactured at the same time (within one year) and then bought his used tires from him.
You can get info on the program here
Tire Connection - Michelin Advantage Program