Unless you really plan to put 300,000 miles in next 10 years, I would look for used tires no older than 3 years that still have > 20% of thread good for at least 60,000 miles.
I was able to find such in 12R22.5 in $70-120 range, while new tires go about $600.
The guys recommend 12R22.5 over metric sizes, but I did not get to the bottom of that.