I really can't say for sure, though I got a couple cheap k-mount lenses around 2000 for a lot less than they go for today - digital exodus.

My purchasing has only been on ebay, and mostly for cameras with parts that will interchange with my Sears KS-2 (I don't consider parts cameras G.A.S.). However, it seems I cannot find them as cheap as a year or two ago, even accounting for increased shipping costs. These variants still don't command high prices, but they are costing more lately.