I have been in the last year 3D Printing for profit. It was very unexpected but my first print was a fidget spinner. My friend wanted me to 3D Print one for him, he showed his mates and a day later i got 5 orders. That was during September. Then it died down. Last month i've been selling a Bitcoin keychain and i have a toooooonnn of orders. So moral of the story. People with 3D Printers find a good model, print it and sell it. This month is a good month to sell printed Bitcoins!