When we first moved to Discourse I tried to look up how much we were paying. Based on the number of page views we get, we’re well up into the “call for a quote” cost category.
I suspect that it’s significantly higher than your $150-250/month range, but I’m not involved at all in the financial side of things here, so I really have no idea.
I also have no idea how much money we bring in from advertising. I have heard that Cecil’s Column was where the real money was and that the ad revenue from the SDMB side of things isn’t worth much. I’ve heard a lot of grumblings about ad blockers so I suspect that’s taken much of the SDMB ad revenue away from us.
The general impression that I get (and again, I’m not involved in the financial side of things so this is just guesswork) is that we are barely keeping the lights on around here.
Message boards in general have been declining significantly in the last decade or so. Many, if not most, have completely gone away due to being financially unsustainable. We have been steadily declining too, but we’re still here, so we’re doing better than most.