For the device: Pricing, say

[spdrun]

For the device:

Pricing, say $400 for the device over 5 years. And it will last 5 yr if you buy good hardware: $80/yr.

Power usage: 40W = .040kW * 24hr * 365d = 350 kW-h @ 15¢/kW = $52/yr

$80 + $52 = $132/yr total.

Three computers connected to the service would cost:
$3.96 * 12 * 3 = $142.56/yr.

Running a behemoth server in a home or small business doesn’t make sense any more. Appliance-type devices might make sense once you scale beyond a few connected devices.