You can find the Russian lenses on Ebay. Also various online dealers deal in them. Watch out for shipping etc. I'd still urge you to look at something like the Pentax lenses. The price difference between a mint Pentax normal lens and a Russian lens won't be very great once you factor in shipping.

Now if you're looking for something like an 85mm lens then the Russians make a lot more sense. Or the fisheyes. But for a normal I'd lean towards getting the best.