Design time involved
overhead for shop and tooling
Materials needed for the knife
costs for external dervices (heat treating for example)
labor needed to make the knife
profit ( ha ha ha )
I don't think supply and demand plays a role. Because if you sell your products below cost, your gonna go broke, so you might as keep the knives and you'll have something to play around with.
I've recently been trying to do some halfway real cost accounting for my knives and man is that a downer. I don't really see how the full timers make a living at it. Hats off to those gents!