I recently got in contact with Matt and asked him to update the lens section with all the new Pentax lenses, which he has done.
Over the years I have been able to spot good deals after a quick scan of the site. Worth bookmarking.
I have no affiliation whatsoever with them - but in these times of rising prices it is a good site to be able to refer to. Obviously it may be more relevant to UK/EU members but there's nothing to say that folks in the US and Aus/NZ couldn't buy from any of the UK stores. We appear to have plenty of KP's for sale through the big camera stores, for example.
The site address is:
Pentax Digital SLRs UK Price Comparison
Hope this is useful.