You don't actually specify what you define as wide angle. I have the K100D super also, and I get along grate with the Sigma Ultra Wide II 24mm f2.8. Its wide enough for everyday use, and faster than the kit lens, also smaller. Manual focus but with the A setting on the aperture ring. And for targets beyond about 5m, you don't have to touch the focus ring anyway.
Also, it seems to be selling rather cheaply on ebay in spite of excellent reviews. Got mine for under £25.
I'm also in the market for a budget wide angle prime - but beyond 18mm, the only one remotely in my "casual bidding" price range that comes up is a Vivitar 17mm f3.5 (that's from memory) - in any case the extra 1mm isn't worth it for me.
There are pentax 15mm lenses, but they sell for a pretty penny. The only other interesting one I'm watching for (and I have no idea on price, cos a copy hasn't appeared on ebay since I found out it exists), is an old Sigma 14mm f3.5
(link) (the one from before they made the 14mm f2.8 which is what google throws up readily).
To be honest though, bargains notwithstanding, I think I'm best saving for a Sigma 10-20mm.