The prices on mil-surps is not going to decrease. I've seen a 400-1500% increase in my lifetime, and it well probably continue.
Buy the best you can afford. Pick a area or type and concentrate on it, become knowledgeable about them. You need to learn what is common and what is rare so if you see a deal you can jump on it.
ETA: +1 on what John said. K's are still priced low, they well double rather quickly. Ten years ago they were $75, six years ago $175, today $250-300.
This is better than bank interest, but only keeps up with inflation.