If you want an activation key to apply to a Windows 10 device, you’ll pay $61 per device for Year 1.

And that Year 1 is significant. Microsoft noted: “The price will double every consecutive year for a maximum of three years. If you decide to jump into the program in Year Two, you’ll have to pay for Year One too, as ESUs are cumulative.”

$61 => $122 => $244

And it’s 100% profit per each device, since there is no ongoing work happening.