Facebook agreed Tuesday to buy the Finnish-based tech startup Pryte, which enables smartphone users to purchase mobile data on demand, the companies announced. The move could help Facebook further its goal of bringing the Internet to more people around the globe, allowing them to avoid costly monthly data plans and instead buy bite-sized, app-specific data packages. Facebook said the deal would help its efforts to bring the Web to underserved populations though its Internet.org initiative. The Pryte team will be an exciting addition to Facebook, the California-based social network giant said in an email.