Comixology is currently offering a free digital copy of Superman #1, first published in 1939. This may be a US only thing, but if you’re in another country and it’s also free there, let me know and I’ll update (thanks to everyone letting me know, list added below).
As described on Comixology:
Featuring the origin of the Man of Steel, Clark Kent’s first day at the Daily Star newspaper, and Superman, who stops a lynching, gangsters, and an execution.
This is probably timed with the latest Superman movie currently out in theaters, where he finally meets Batman and Wonder Woman on the big screen. If you’re looking for negative reviews, those are easy enough to find, so here’s a mostly positive one. Speaking of which, the first appearances of Batman and Wonder Woman (and her continued origin story) are also still free.
And while not free, you can also get Actions Comics #1, with Superman’s first appearance for the low price of 99 cents. Compared to the cost of a near mint original copy, if you can find one and the owner is willing to sell it, that’s a really great bargain.
I’ve said it before and I’ll say it again, being able to get these Golden Age issues for free or just one (US) Dollar is one of the best greatest features of digital comics. Enjoy!
This is also free from Comixology in the following countries.
Brazil (thanks harmagedom!)
Australia (thanks Shampyon!)
Philippines (thanks zack_falcon!)