Not to flog the standard source, but KEH has a nice selection of real pentax screwmount lenses right now. The bargain choice would be the super-takumar 105 2.8, though the 85 1.8 is also there, or the 100 f4 macro. They'd be my first choice.
I've shot quite a bit with my scavenged and refurbished ones in the last year, and they're nice camera. Probably going to list them here shortly though, as I prefer my old Nikon F for most purposes. Nothing wrong with them, but I have too many blooming cameras around here.