Tired of paying the ridiculous markup for brand-name computers, even ones you build yourself? Thanks to the miracle of 3D printing (miracle still being perfected) you can now print yourself an entire computer on the cheap—assuming you've got free access to a 3D printer, and don't need anything more than a basic calculator.
The plans for Chris Fenton's Turbo Entabulator—an all mechanical computer that's as slow and basic as you can get—are available for download on Thingiverse so you're saving some money there. And despite its basic functionality, it will still feel cool telling your friends you just got a Turbo Entabulator. That's a big step up from the base model Entabulator, and since it uses punch cards instead of store-bought software, it's safe to assume that eventually this thing could pay for itself.