A quick googling suggests it's probably in the $10-20 range, though there's obviously variance in how often you run a load, and electricity costs in your area.
Not literally "a few" in the sense of like three or four bucks, but a very small price compared to the dozens of hours of labor you're saving each year.
A high efficiency front-load washer can be remarkably efficient. I bought an LG MW3400 last year and here's what the energy guide label says: $12 estimated yearly cost when used with with an electric water heater, $10 when used with a natural gas water heater.
That's based on an energy cost of $0.12/kWh for electricity and $1.09 per therm for natural gas, and 6 loads of laundry per week.
The estimated annual electricity use is 100 kWh.
It's an interesting washer technically. It has LG's "smart diagnostics" but it does not have WiFi. Instead it sends the diagnostic data to the LG app acoustically. You tell the app to get the diagnostics, then press and hold the TEMP button on the washer. The washer then sends the data using what sounds like the modems we used to use in the dial-up days.
Note: some review sites, such as Consumer Reports, say that it does have WiFi. My guess is that they assumed that because of the smart diagnostics which do use WiFi on models that have it.
I doubted this too, and since I just got a new one (ok, it's 5 months old but I haven't removed the paper), I took a photo: https://imgur.com/a/9EsB6pm
I wouldn't call $22 a few dollars.
And it's missing the detergents.
That said, this one has one of those detergents dispensers. And my detergent now seemingly lasts forever, indicating that I've always used too much.
That doesn't sound credible.