It doesn't literally print money, but it's close!
https://www.howtogeek.com/7-ways-your-3d-printer-can-pay-for-itself/?utm_source=dlvr.it&utm_medium=blogger
https://www.howtogeek.com/7-ways-your-3d-printer-can-pay-for-itself/?utm_source=dlvr.it&utm_medium=blogger