@djoerd
Yes! I had heard that #JMLR has significantly less production costs... something like 6.5 USD per article

https://blogs.harvard.edu/pamphlet/2012/03/06/an-efficient-journal/

Also see this discussion: https://ask-open-science.org/28/how-much-does-it-cost-to-publish-an-academic-article

P.S.: #JOSS (https://joss.theoj.org/) has net 0 costs by relying on GitHub for everything.