EXCLUSIVE

Donald Trump shut down negotiations to get a huge rock band at one of his Inaugural balls ... in order to cut costs and potentially save tens of millions for charity.

Inauguration sources tell us the Committee was close to landing a legendary group -- one that's in the Rock & Roll Hall of Fame -- but when the President-elect found out they wanted more than $1 million for the gig he pulled the plug. We're told Trump implored the rockers to reduce their appearance fee -- but when they refused he told the Inaugural Committee to move on to other artists.

Mind you, there's plenty of dough. The Committee's reportedly received more than $90 million in donations, but we're told Trump instructed all involved to keep expenses in the low millions because whatever is left over is going to charity.

As we reported ... the Liberty Ball and Freedom Ball will now feature soul legend Sam Moore, as well as Grammy nominee Travis Greene. While organizers are tight-lipped about naming all the acts, our sources say you can expect an eclectic lineup -- ranging from dance to country to gospel -- and everyone's doing it for free or a greatly reduced rate.