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.

Ah crap what's with capitalists taking the opportunity to exploit resources that could've been free? It may happen again with the current new "gold rush" that is AI if this keeps up, since singularitarians claim that AI will create some sort of labor-free utopia for everyone.

He built a tower which could deploy usable electricity into the atmosphere. The ionosphere acted like a reflectors of energy which could help sending electricity over a long distance.

Sadly it was destroyed in the world war (i think).

You can search about Tesla on YouTube. There was a well made documentary on his life.