Based on the OP's post, I am assuming he or she has a body with a wired release socket ...if the body is a K-x or K-r, see this DIY thread-
https://www.pentaxforums.com/forums/do-yourself/186110-make-wired-release-any...ir-camera.html
I just purchased a Neewer generic CS-205 compatible wired release for my K-30 for a bit over US$5. It works fine. For another US$4, I purchased 2.5mm-3.5mm stereo M-F and F-M adapters which allow me to use any cheap 3.5mm stereo headphone extension cable.
Just so you know, generic wired releases for the Canon Rebel T2i, XT, XTi, XSi, XS, T1i, EOS 550D/1000D/450D/400D/350D/300D, are also compatible wherever you would use the Pentax CS-205.