There is a tendency to talk about "the poor" as an extreme case, and "the wealthy" as an extreme case. But in doing so you make the entire problem irrelevant. As you say, the extreme poor at that time does not write, and the extreme wealthy at that time does not care.

The question is only relevant for a more "normal" case where that both writes and is price-sensitive. Say, a student, a public writer, an accountant, a letter or litterary writer.