The cheapest I own was free, and it actually gets used - a Spyderco Bug that was being handed out for free at their booth at Blade last year.
The most expensive is a Busse Killa Zilla (~$700), and I'm trying to sell it because I have no use for a kukri that costs that much. I beat on it, sharpened it up (factory edge was terrible), and decided I will never carry it so it's nothing more than a toy. For $700, I can get some much more fun toys.