In September, we (the Surrey nuclear theory group) are hosting the 24th European Few-Body Physics Conference. One of my main roles on the local organising committee is to arrange publication of the proceedings, and I'm pleased to have organised this with the journal SciPost Proceedings. Unlike most (all?) of the other regular journal options, SciPost proceedings are free to publish in and free to read. The costs involved in the whole publication process are pretty modest, being the web–hosting of the papers, and the provision of a doi for each paper. All other tasks, such as managing and implementing the refereeing and editing process is done, as usual, free of charge by academics, who are paid a full time salary to be academics.
Those low costs of running the journal are provided by sponsors, and I'm happy to see, from attending a presentation about Plan S last week, that the University of Surrey are sponsoring SciPost. The amount paid by the University is minuscule compared to traditional journal subscription costs, and amounts to the cost of paying for a couple of Article Processing Charges to a regular journal.
I'm excited to go through the process of editing the proceedings (i say now, before the real work starts in earnest), and I'll report back here how it goes later in the year.