Nicki Minaj -- I Got Lil Wayne a 1,000-pound T-REX for His Birthday

What do you get the man who has everything? Nicki Minaj figured it out ... getting Lil Wayne one of the craziest awesome gifts ever for his 30th birthday ... a tiny 3-wheeled $70,000 sports car called a T-REX.

Sources close to Nicki tell TMZ, the new "American Idol" judge got Weezy a Campagna T-Rex 14R -- a two-seater motorcycle-car hybrid that's ultra-lightweight at 1,040 pounds ... and FAST, reaching speeds of 150mph.

The trike retails for roughly $50,000 but we're told Nicki tricked hers out as a special "thank you" for all Wayne's done for her career -- dropping a total of $70,000 on Weezy's gift.

We're told the car-thing was delivered to Wayne at his giant 30th birthday bash in Hollywood last night -- and the rapper was stoked about the present.

Young money.