T-Pain Sues Young Money for Royalties on Lil Wayne's 'Tha Carter III'

T-Pain wants to know if Lil Wayne "Got Money" for him ... as in the more than $500,000 he says the rapper owes him for services rendered on "Tha Carter III" album.

T-Pain's company, Nappy Boy Productions, is suing Young Money ... saying he produced Wayne's track, "Got Money," which also featured T-Pain. Further, TP says one of his artists, Young Fyre, produced "How to Hate" on "Tha Carter IV."

The deal, according to docs, was that Young Money would pay T-Pain some royalties. According to the docs, there should be a bundle ... because 2008's "Tha Carter III" sold more than 3.2 million copies ... and that's in the U.S. alone.

T-Pain believes he and Young Fyre are owed more than $500k.