Britney Spears showed her charitable side this week when she handed a tramp $300.The 'Toxic' singer was driving off after withdrawing a large amount of money from a cash machine on Wednesday, when she came to a stop at a Los Angles intersection. While her car was stationary a homeless man approached and knocked on the window. A source told Us Weekly magazine: "Britney rolled down the window and handed the guy $300. She said, 'Good luck and happy New Year!'"The guy almost had a heart attack."Britney's generous payout is apparently all part of her new positive outlook for 2007.The source added: "Britney wants to do good - for herself and the world.That's what she's all about this year."On the same day, the 25-year-old pop superstar was also seen picking up the latest addition to her family - a new puppy. Britney and her 15-month-old son Sean Preston visited the Pets of Bel Air store where the singer forked out $3,200 for the tea-cup apple head chihuahua, which she has reportedly named Snow White. Britney owned three other chihuahuas, Lucky, Lacy and Bit Bit, when she was married to Kevin Federline. It is not known if she still has the pooches.