I found in other web-based financial tools like Turbotax online and Simpletax, they require the user to go through basic questions to build the profile. May be a good idea to incorporate the same, when users sign-up they go through a series of questions (how much do you pay for rent, how much for groceries, do you have kids? If yes how many kids, how much allowance per child? etc) and this builds their initial ledger.