iOS: If you don't have a generous data plan with your mobile phone carrier, then you likely keep pretty close track of your data usage so you don't go over. While a lot of different apps exist to help you do this, DataWiz is a tracking app that has all types of useful features to help keep your data bill down.
DataWiz tracks the amount of data you send over your carrier's network, analyses it, and then creates predictions for your data usage over time. You can set it up so it alerts you if you're about to go over your cap. You can customise it for a variety of settings and billing periods. What's especially handy about DataWiz is that you can create alerts for daily usage as well. So, if you happen to be using a lot of data one day, you can set DataWiz to calculate ways to make that up over time. Essentially, DataWiz is a tool that not just lets you track your data usage, but actually get a good overall view of what you use, and when you use it. DataWiz is similar to our favourite data tracker, Data Usage, but it's free.