Are you too broke to get a gyroscope? Do you also have a crusty fidget spinner lying around? Well, you can make a gyroscope out of it!
Same principle after all: They need to spin quite fast to do some physics stuff. So, this model has a shaft to fit a typical 608 bearing (8277) in a typical fidget spinner. Use a string to accelerate the thing to godspeed so it actually balances.

15% infill, no supports.