I used to buy used tires. Definately not the best for anything, but was cheap and convenient at the time.
Now I'm generally looking for best traction for the uses intended. Not putting a lot of miles on - so its totally worth it to me. Everyone is different.
A set of 1400 dollar tires lasted 36K miles. Might get another 8 to 10 if I go down to the bone....Bad thing is the truck and the edge both need tires. 10 expensive tires.