Mobile data usage is on the rise globally. In emerging regions, mobile data is particularly expensive and suffers from the lack of price and data usage transparency needed to make informed decisions about Internet use. To measure and address this problem, we designed SmartBrowse, an Internet proxy system that shows mobile data usage information and provides controls to avoid overspending. In this paper, we discuss the results of a 10-week study with SmartBrowse, involving 299 participants in Ghana. Half the users were given SmartBrowse, and the other half was given a regular Internet experience. Our findings suggest that, compared with the control group, using SmartBrowse led to a significant reduction in Internet credit spend and increased online activity among SmartBrowse users, while providing the same or better mobile Internet user experience. Additionally, SmartBrowse users who were prior mobile data non-users increased their webpage views while spending less money than control users. Our discussion contributes to the understanding of how forward-looking ICTD research in the wild can empower mobile data users, in this case, through increased price transparency.