Manny Pacquiao & Floyd Mayweather -- A-List Celebs Can Score Free Seats ... But It's COMP-licated

If Will Smith, Leonardo DiCaprio or Rihanna want FREE seats to the Manny Pacquiao-Floyd Mayweather fight -- it'll be no problem at all -- as long as they're down to be a walking billboard.

Tickets are in such high demand, fight promoters aren't handing out comped front row seats to high profile stars like they usually do. Instead, they'll be forced to pay up to $100k or more ... just like normies.

But we've learned there's another option. If a celeb is willing to endorse companies by wearing logo-emblazoned gear at the fight -- that company will eat the ticket cost.

For instance, we're told VOCO Vodka & Coconut Water has already made such offers to Leo, RiRi, and Big Willie ... in exchange for front row seats.

We know what you're thinking, but sorry ... you in a VOCO cap just ain't the same as Rihanna in one.

Enjoy the PPV.