A collection of super-rare signed contracts for some of baseball's biggest names -- including Mickey Mantle and Hank Aaron -- is up for sale ... and they're all expected to go for insane prices!!
RR Auction tells TMZ Sports ... Mantle's 1953 deal with the New York Yankees (with a $17,500 salary) headlines the lot ... and the historic pieces of paper are estimated to land a $50k price tag.
Mantle's contract is signed "Mickey C. Mantle" ... in which the legend agrees to provide "skilled services as a baseball player during the year 1953," according to the paperwork.
"As one of Mantle's early Yankees contracts from a World Series season, this is an absolutely spectacular, museum-quality piece," Bobby Livingston of RR Auction says.
On top of Mantle's piece of history, Aaron's Atlanta Braves contract for the 1974 season -- when he became the all-time home runs leader over Babe Ruth -- is also available ... and could fetch more than $10k!!
Worth noting ... Aaron's contract was worth $220k for the '74 season. He later became the highest-paid player in the MLB in 1975, when his salary jumped to $240k.
There are a bunch of other signed contracts in the lot from legends like Rod Carew, Whitey Ford, Bob Feller and more ... and they're all available until June 10 on the RR Auction site.