Dollars are pro rata: a plan’s price divided by its credits, times the book’s. For monthly plans, the effective cost per book is higher if you leave credits unused. Monthly credits expire at the end of the billing period and don’t roll over. Free signup and one-time pack credits don’t expire.
Any paid plan includes PDF, EPUB and DOCX downloads. Books delivered during a confirmed paid period, and older books you download during one, keep their download rights after cancellation while your account remains open. A credit pack bought on its own adds credits for writing; bought from a book’s page, it also pays for that book’s files. The free credits write books you can read and edit in full in the app.
Extras cost more: web research adds 5 credits to a book, and regenerating a chapter costs 13 credits on a lead magnet.