ANDY Roddick is $150 richer after winning a bet with Virgin heir Sam Branson. The tennis champ was vacationing on Richard Branson‘s Necker Island when son Sam challenged him to a set. Branson had one condition — right-handed Roddick had to play as a leftie. A source told Page Six, “Even with the handicap, the result was a convincing victory for Roddick. He thrashed Branson 6-0.” Sam could afford it — he’s heir to a $2.5 billion fortune.