“may be” addresses it, right? It can be less for people who are life members and publish alone ($499 for 5-a-year), and it can be quite high for the common-case of a team of 5 publishing 1 article in PeerJ. I don’t know what is reasonable — I’m guessing $300 an article covers what I want most: The ability to sustain quality, to face-down lawsuits and hate-campaigns directed at editors from aggreived parties criticised in articles (for instance people who don’t like that their business based on eye movement desensitisation is shown to be bogus, or who believe academic freedom only obtains for their values). To update the interface year on year, and be profitable, so it survives for 100-years. I’d like nothing more than for PeerJ to become that vehicle.