Yes, marketplace sucks in europe
A good place to find some Pentax stuff is on ebay, for exemple. if you have in Romania some website were you can post some annonce, go on it.
Website of resseller are good too. Even small shop that buy some second hand stuff. sometimes you can find some good things.
For the Market lense : as you could see, some people ask some incredible price for some lenses (like 1500$ for a 85/2 !), but in fact, in the users's reviews of lenses you can see some average price, wich is often the one you can found in the marketplace. Depends on what people are ready to pay, and how much money the seller wants. that's it !