I'm buying mines from Amazon when I can.This is the cheapest I've found it online so far:
Look at the "Other Sellers" links on the right side of the page. Blade Shop has it for $72.74 with free shipping.
That's where I got mine.
Keep an eye out on your local craigslist as well. The BK2 is such a tough knife that it would be extremely difficult for a person to damage one beyond the point of simple resharpening.