Paper Machines

anipigside

You can make anything out of paper. This flying pig is an example of making a crank-based automaton from paper. You cut out the pieces and glue them together to create a machine. No 3D printing required. There are also gears that can be made from paper - it is recommended to get a thick stock of paper (cards, cardboard) otherwise, the mechanism may not have enough rigid parts to operate. For electronics, one can use cheap inkjet printers to create circuits. To make circuits by printing them requires special ink containing silver nanoparticles. I didn't see a discussion of how one would make a switch (e.g., transistor) but research on thin-film transistors has been ongoing, so it should eventually be possible for the average consumer.  Then, we can mix our own ink, or buy it ready-made with reusable print cartridges.