Writes Bleeding Cool, "Note the Superman line item next to the amount $130. Also note the total $412, with other line items including “D.C”, ”Adv”, and “Fun”. This would probably correspond to payments for work in Detective Comics, New Adventure Comics, and More Fun Comics, where Siegel and Shuster had strips such as Doctor Occult, Federal Men, and Slam Bradley published just prior to the debut of Superman."
The legend is that the writing/artist duo sold their rights to the Man of Steel for $130, and here's the documentation to back it up. Who could have known that some 70+ years later this payment would be part of the legal system.