The plan I'm looking at says it costs $300, however, I already have some of the materials needed. Before I moved back home when my mother died, she had rented the house out. One of the former tenants had gotten a $700 electric bill, and this was in the early 80's. I have been able to cut it in half by improvements I have made, but I still want to bring it down more.
If you're really interested in home power - I'd suggest a subscription to Home Power magazine. They go into the nitty gritty details on all the various technologies and costs associated with installation. Wind power, unfortunately is not very efficient, and is costly to implement and maintain. Solar power is more efficient, although an installation that can drop your electric bill to zero, even with Florida's excellent incentives, is still a very long term investment - on the order of 10 - 20 years before you break even. Still, if you have the money to invest long term, I think it's a good investment to make.