Rental company Hertz said Tuesday it is updating its online shopping website to allow customers to secure financing, get a trade-in offer and do just about everything else a buyer would need to purchase a vehicle.The move is a significant step for Hertz's online retail presence. Previously, the company's HertzCarSales.com website had only offered listings of vehicles. Most of the purchasing process happened at Hertz's retail locations, of which there are 45 in the United States."Our new e-commerce platform ...