According to Wikipedia the cost of electricity from modern nuclear stations is roughly comparable with sources like coal - which surprised me:

http://en.wikipedia.org/wiki/Cost_of_electricity_by_source

What I don't know is how much of the cost of nuclear power is the much higher level of safety precautions they need.

I haven't seen any projected costs for DEMO which might well be the first fusion power plant (DEMO is the proposed successor to ITER):

http://en.wikipedia.org/wiki/DEMO