I was lucky enough to get a free m1. That thing uses 10w or so when you remove the stupidity and install Linux on it. But even if you have to buy a Pi - it’ll pay for itself in a few months of not paying for streaming service.
Let’s go crazy and say $. 20/kWh. 10÷1000×8760×.2=$17.5/year. Not free, but pretty damn close.
They don’t give it to you at 0% apr. Most credit cards have insane rates above 20%. They can and will come after just about everything you own.