NFL Draft: Sammy Watkins -- The First Thing I'll Buy with NFL Check Is ...

Sammy Watkins-- arguably the top receiver in the NFL Draft -- is just hours away from being a multi-millionaire ... and he tells TMZ Sports he already knows how he's gonna spend his first check.

But the coolest part about this clip isn't the money -- it's the fact that Watkins (who's leaving school early to turn pro) says he's still dedicated to earning his degree in communication studies.

"I think I'll go back every Summer," Watkins says ... "I love Clemson."

6:15 AM PT -- Ummmm .... maybe Sammy spoke too soon!!

Right after we spoke to Sammy, he posted a video to Instagram showing off a bunch of super expensive jewelry ... including gold watches and gold necklaces.

BALLIN'!!!!!!!