Re: 911(964)Turbo 3.3
Very dependent on condition. Nice one around $35k, I think. Extraordinary one would be significantly more. And of course the 1994 3.6L is quite a bit more again (really nice 1994 3.6L is worth high $60's).
Don't overlook the 930 3.3L - those are a bit more raw and exciting in my opinion...
BTW, a 964 Turbo is known as a 965 (might help with the search)