Like many surplus items, when a large batch is imported, the market becomes saturated, and prices are low.  As time goes on, the supply is reduced, and prices begin to climb.

You can either buy one now, while the prices aren't too bad, or wait and hope that another batch will be imported and the prices go back down.  The latter approach sometimes works, but often it results in never getting the gun you want at anywhere near a "reasonable" price, much less a "bargain" price.

The lesson: when you see a surplus item cheap, snatch it up ASAP!  

-Troy