All it'll take is some a lot of cash for COVID-19 charity ... and, get this, the New York Giants legend will even hand-deliver it for ya if you offer the most!!!

The 39-year-old newly retired QB just accepted Michael Rubin's all-in challenge ... and the package he's offering for a big coronavirus donation is one of the best we've seen so far.

Manning says the 2012 Corvette Grand Sport Convertible Centennial Edition he won for beating the New England Patriots in SB XLVI is officially on the auction block.

It's a pretty amazing ride ... it's only got 5,830 miles on it -- and Eli says he'll drive it out to you and even have lunch with ya if you win it!

"Maybe I'll even teach you how to handle this bad boy," Eli says.

Pretty cool offer, right?? But, did Cooper Manning just one-up his little bro?!?!

The third Manning brother just posted his all-in challenge package offer ... and we gotta say, it's DEFINITELY the funniest we've seen yet.

Of course, Cooper's just playing around ... but little bro Peyton sure as hell ain't with his donation package -- the future Hall of Famer is offering up a round of golf AND dinner!!