Sounds like the expectation is for somewhere in the 3.0-3.5 mile per kWh range for the Mach-e. My home electric rate is $0.1015/kWh. Even at the more conservative 3.0 miles/kWh estimate, that's 3.4 cents/mile.
Compare that to my 2013 Escape that averages 25 MPG. With gas at $2.50/gal, that's 10 cents/mile. So compared to a vehicle like that, the Mach-e costs 1/3rd as much for fuel (if fueled at home). Over 12,000 miles/yr, that's $1200 in gas vs $400 in electricity. An $800/yr savings. ($8000 over a decade, which is something to consider when factoring in lifetime purchase/ownership cost.)
That's assuming one charges at home though. That savings seems to disappear if charging at an Electrify America station. I'm a little confused at their pricing levels and how they would fit for the Mach-e. They show 3 different rates (1-75 kw, 1-125 kw, and 1-350 kw). The Mach-e will charge at up to 150 kw. So does that mean we pay the 125 rate or the 350 rate? When I calculate the rate for 125 kw, it appears to work out to almost triple my home rate. In other words, nearly the same as gasoline. (If I did the calculation right.)