It’s not so much that Nikola Tesla discovered AC as much as he figured out how to make use of it. I believe generators give alternating current by default as they spin around, but they’d use commutators to convert it to DC.

Source: saw one of those Discovery Channel shows.

Either way, Tesla was a brilliant engineer, but it shouldn’t take much to understand that it takes energy (that has to come from somewhere) to produce electricity. That money has to come from somewhere, and I wouldn’t want to see a gigantic factory or mansion or whatever paying the same amount (even if $0) compared to some grandmother in Vermont keeping the lights on.