Car renting meets car sharing? Avis Budget Group has agreed to buy Zipcar for around $500 million, the Wall Street Journal reports. Avis will pay $12.25 per share, a 49% premium over Zipcar's closing price Monday. Zipcar's stock has risen in recent months as car sharing grows in popularity, and shares were recently at $8.78. "We see car sharing as highly complementary to traditional car rental, with rapid growth potential and representing a scalable opportunity for us as a combined company," says Avis' CEO.