If you're looking to sell prints, it helps to know your costs. Using the Canon PRO-300 as an example, Keith answers some questions he's often asked about selling your work.
There is very little direct cost of printing information available, but there is one particular web site Keith often uses. It's Red River paper in the US and the page he refers to in the video is:
https://www.redrivercatalog.com/rr/cost-of-inkjet-printing.html
Test images are available at:
https://www.northlight-images.co.uk/printer-test-images/
This is part of Keith's Business of Photography' playlist.
All of Keith's photography business related articles and videos are referenced on the Northlight Images site at:
https://www.northlight-images.co.uk/business-of-photography/