Reddit mentions of Sandisk 4GB MicroSDHC Memory Card with SD Adapter

Try doing it on 10 ~5 watt Raspberry Pi Zeros that cost $5 each but has no built in wi fi.

Adding a Netgear usb adapter on the cheap costs an average of about $8 each for the first 10, accounting for shipping. (These guys use less cpu in favor of a hardware chip, needed for single core cpu.)

Adding the necessary micro-sd card to host the operating system and programs costs $5.28 each with free shipping. (Price from offers)

Taking your calculation of $2102.40 per computer and assuming that Spotify doesn't notice 10 connections from the same IP address for an entire year and there is no technical downtime;

Internet cost

$70 × 12 months = $840

Cost to operate a computer in a year.

0.003 kW (5 W @ 60℅ utilization) × $0.10/kWh × 24 h × 365.25 days = $2.63 per year.

Please correct if I was wrong there :O

$2.63 × 10 computers = $26.30 per year.

$2102.40 × 10 computers = $21024.00

$21024 - $26.30 = $20997.70 per year.

Holy shit.

And the cost of the equipment?

10($5 + $8 + $5.28) = $182.80

76 hours 23 minutes 14 seconds or exactly 274994 seconds to recoup $182.80, accounting for the cost of electricity.

One common misconception is that computers always use all the power as rated in the power supply. That is absolutely not true and will cause you to over estimate. In reality, computers are almost always never at full load, most of the time, computers are left idling and using much less power. This is how programs such as BOINC take advantage of your otherwise idling utilizations.

The reality is more towards 30 - 40 percent daily utilization. However, since the Raspberry Pi zero is a single core processor that is weaker than any smart phones on the market, I can only assume that software decoding of the Spotify music would use quite a bit of power.

Feel free to check just how many instances of Spotify the Pi zero can handle to maximise profit per computer.

Also... Feel free to expand from 10 Pi zeros after the 3rd day. Maybe even make a whole data center of raspberry pi zero to rent for contributing to Spotify income and take a cut from the participating artist as rent.

Use a VPN or a few VPNs. Maybe even route through multiple Tor instances. (please don't hog a single relay path, do spread the traffic around.)

That way, you have effectively spoofed your rack of raspberry pi as individual customers playing music.

Maybe go ahead and shuffle a playlist of artists to play at different times or even set them to log out and back in as different users with different relays to avoid the ban with minimal downtime.

Good luck selling artists a money making machine!

You can get one on Amazon for under $7 including an adapter so it'll fit in a standard SD slot.

I forget most people don't have smart phones w/data plans. I live in a very technology-centric place (the land of Microsoft), and I know I take my always-connected status for granted. I can't imagine not having a data plan now. Like, I'd give up almost everything else before giving up my iPhone. I'm that pathetic. :)