Don't forget the 2x4K monitors, network cable (if not using wifi), case, keyboard, mouse, assorted USB devices, desk and a building to house it in
All I had to buy was the Pi, one microHDMI cable and a microUSB to USB-C adaptor for power. I'm not even using the microHDMI cable at the moment as all my Pi run headless.
XP? UrghThe other unseen costs are time and loss of earnings. Raspbain - while very good - doesn't hold a candle to Mint (which is still pretty XP-like).
Raspbian (note spelling) is pretty good. I've had very few problems with it.
Have my Pis cause loss of earnings? No. Possibly the opposite, although I'd like to do more there.
Loss of time? Yes, because I've had so much fun working on them
Yes. I used to have a few PCs around my house running 24/7 and burning electricity. They have all been replaced by various Pis and saving me a fortune, plus the Pi 1B that controls my heating saved it's cost in a few months.We do love the noticeably cheaper electricity bill after switching from 8 desktop PCs. Also, savings on air-con and much much quieter office now we don't have that low-level hum we did from the PCs before.