The neon transformer I used is powered by standard 115 VAC, 60 Hz line current. The output was 15,000 VAC. That transformer is lethal by itself. It will generate a nice "Jacob's ladder" with a couple pieces of stiff 12 gauge wire on the output terminals.
You can build a safer Tesla coil than the one I built or the large economy size done by RadioAstronomer. There is a book titled Electronic Gadgets for the Evil Genius that includes project plans, parts lists and approximate costs. I bought a copy of the book to play with the anti-gravity lifters. The book projects are easily implemented by any electronics hobbyist. You might have to place a mail or internet order to get some of the odd parts.
One of the Tesla coil projects runs off the 115 VAC line and produces a 250,000 volts. It can produce a 12 inch spark. The Tesla coil operates at a frequency around 500 KHz for this model. Nominal cost is $100. The driving transformer product 6500 volts at 23 milliamps. About 1/3 of the voltage of my neon transformer and much lower amperage.
If you have more $$$ to spend, there is a Tesla coil project in the book that will generate a 30 inch arc. Duty cycle is limited to about 10 seconds on. It produces substantial amounts of ozone. The project plans warn that a Faraday cage may be required for safe operation.