It’s not common, but it does happen. Andy Weir, author of “The Martian” and “Project Hail Mary”, originally gave his work away for free online on his website. He only self-published to Kindle (for the lowest possible price setting, 99 cents) because some of his fans didn’t know how or didn’t want to manually install his home-rolled ePubs on their devices, and begged him for the Amazon/Kindle distribution.