Hi,
This is going to be fun; the cheap but excellent value for money lenses are the former USSR made ones that came with the FED, Zorki, etc cameras. You can get them easily in 35, 50 and 85 mm (and 135mm but I've no experience of it).
They are rather old fashioned lenses and many people like them for that but the Industar-61 and 61 L/D are good and not so old fashioned. They are f/2.8 but there's the Jupiter-8 at f/2 and a Jupiter-3 at f/1.5.
The problem is, they are cheap and people will mess around with them and take them to bits rather than ask a technician with the tools and experience to check them. So you get them with lenses reversed and so on. Also, during the cold war the USSR, our former ally, was denied access to things our former enemies had like modern lubricants and so these are best replaced due to their age (just like old Leica ones, FWIW).
Having said that I'll add that I have bought these lenses at prices from 50 pence (about 65 US cents) to a fiver (about US$ 6.50), checked them and been pleased. I don't know what they cost to get sorted out - as mine seem OK - but a Leica lens needed the full treatment and cost about UKP 20 when done by the experts. Often the lenses are sold with cameras for equally silly prices.
I'll go along with the others about CV lenses and, as it's all been said, will say no more.
Regards, David
PS Sample photo's from the USSR made lenses in this lot of threads:-
http://www.rangefinderforum.com/forums/forumdisplay.php?f=34
