Here's my answer for this (with data!): For the month of July, I charged 440.0 kWh. I averaged 94% efficiency while charging, so the chargers actually used 469 kWh. There were 35 charges, for a total of 66 hours spent charging. My total electric cost is 15 cents per kWh (my plan doesn't have peak/off-peak). I did no charging at superchargers in July.

In that timeframe, I drove 1314 miles. 355kWh were used while driving, giving me an average efficiency of 3.7 miles per kWh. You'll note that I used 85 fewer kWh driving, that's because thosed 85 kWh were used to precondition my car, keep the AC running while I'm in the store or on a bike ride, etc. Super wasteful, but it's so cheap that I can't help myself).

So to break it down: 15 cents per kwh * 469kWh = $70 to charge, $12.75 of which was just used for climate control while not driving.

My last car was a 2016 Honda Accord Touring V6 which, in my area and with my driving style, averaged about 22mpg (lots of steep hills, 85mph driving, and stop and go traffic. I live 15 miles from town by interstate and town has lots of traffic).

According to AAA, the average cost of gas in PA is $3.87 (I know that price changes, but the math gets harder if I look up the price of gas each time I would have had to fill the tank so I'm just taking the current avg). 1314 miles / 22mpg = 59.7 gallons of gas * $3.87 = $231.

For extra fun math, looking at purely fuel costs, the Accord would cost 17.5 cents per mile to drive (not including the fact that I'd need an oil change every 4 months, transmission fluid every year and a half, etc).

My current car at current electric rates costs 5.3 cents per mile to drive.

Additionally, i'm planning on getting solar in a year or two, which should bring my cost down to effectively zero. AND, we can charge for free at my wife's work when she's in the office (as well as at the park I bike at), but she wasn't in the office at all in July; we both worked from home full time last month.

TL;DR: my Model 3 Long Range costs about a third as much per mile to drive as my similarly sized Honda Accord did before I sold it