David Gaughran refreshed his big list of vetted promo sites for 2026 - deal newsletters as Groupon-for-ebooks, why discount runs still anchor a lot of indie careers, BookBub's huge reach (and picky gate), and cheaper fills when you can't land the marquee slot.
He likes stacking promos one after another instead of firing twelve at once, side-eyes bundle packs full of dud sites, and runs through genre promos, series bundles, list builders, and cheapskate options. There's also a link out to his free marketing course.
(Shortened and summarised to avoid devaluing the source)