Not everyone has the luxury of waiting until the local Army/Navy surplus store has these shirts in stock for $20. I wouldn't recommend waiting, anyway. Better to spend those hard-earned dollars on something useful than wait until those hard-earned dollars can only buy pesos.
I've used this, and LOVE it. Feels good, fits great. Some complain the shirt sleeve size is too big. For the record, I did not.
Even if it IS too big, that's just more room for secret gear you can fit in the sleeve pockets. Or, you can fill those arms out a little bit, private!
Either way, this shirt is the recommended Gear o' the Week: