In 1939, shortly after Ray Bradbury graduated from high school, he started a zine called Futuria Fantasia. It featured a lot of his early fiction and some essays, and you can read all first four issues online at Project Gutenberg.

Bradbury started Futuria Fantasia by borrowing $90 from Forrest E. Ackerman, and used it as a soapbox for his ideas about futurism, as well as a venue for his early SF. As Open Culture notes:

The first issue, available free from Project Gutenberg, includes Bradbury’s story “Let’s Get Technatal” (written under the pseudonym “Ron Reynolds”) and poem “Thought and Space.” The second issue includes an article he wrote under “Guy Amory” and his story “The Pendulum.” The third includes a Bradbury editorial, the fourth another editorial and the pseudonymous stories “The Piper” and “The Flight of the Good Ship Clarissa.” “I hope you like this brain-child, spawned from the womb of a year long inanimation,” the ambitious young Bradbury writes in his introduction to the summer 1939 issue. “This is only the first issue of FuFa … if it succeeds there will be more, better issues coming up.” Three more would, indeed, emerge, but surely even such a predictive mind as Bradbury’s couldn’t imagine what his career really held in store.