A lot - especially for Pepsi.
Here's a clip from the great three-part Canadian documentary "The Cola Conquest," which should be required viewing for anyone interested in the cola wars and advertising (as I always like to say, "The history of Coke is the history of advertising").
Marketing calls Jackson an advertising icon today; in the 80s, Michael Jackson "opened the floodgates to big companies signing up celebrities as brand ambassadors."
For $5 million Michael Jackson - the biggest star of the day - rewrote and rerecorded Billy Jean - his biggest hit - and appeared in the spot. Whatta deal!
Despite what we know about Jackson and kids, there's no denying that this ad still has the goods: