If you’re uploading poster artwork on the other popular print on demand websites, I highly recommend looking into uploading your files to displate.com.
I haven’t added any new art to my profile in 5 months, but I’ve consistently earned ~$300 per month since the last upload (finally, some true passive income).
In fact, my earnings are steadily increasing and I’m expecting the holiday season to be incredibly profitable because last year, in December, I made an all time monthly high of $600.
EDIT: Turns out they aren’t currently accepting new artists. Sorry everyone. Feel like I’ve led you on. :/