Fair price expected to pay for a Pentax F or FA 50mm?

Am considering looking for a good version of one of these as it would go well with my MZ-7 and Ektar and the K5 as a portrait/short telephoto lens. F1.7 or f1.4 though I probably won't use the 1.4 often at that as high ISO is so effective on the K5.

Have not looked at the film AF lenses and am interested as to what is a fair price for these? Decided that I should invest in some glass to move a step up from the WR kit lens (which is pretty good in itself, but Pentax are known for primes aren't they?!). I'm concerned over any perceived law of diminishing returns with these things though?

Not sure I can justify DA* though.......!!! Though appears that the prices keep going up and so could horribly be condsidered an investment of sorts...?

A good used copy of the F or FA 50mm f1.4 should cost you in the region of £200. SRS currently have them brand new for £260.

Or SMC F 50mm f1.7, up to £150 in good used nick.

Cheers guys!

Now to find the right one....

Have sent you a pm....

Jon