Toshl Finance Expense Tracker's design is clean and simple to use. When you add a new expense, Toshl pops up a full-screen calculator with large keys in order for you to enter the amount. Then you're taken to a second screen on which you can assign a tag to the item and opt to make the expense recurring if you want. OS reviewed: Android. Other Oses available: iOS, Symbian, Windows Phone, BlackBerry.