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.