Trip It Easy is an app that give you the opportunity to convert and store your expences in your current currency, and it's ideal for travel across the world in countries that don't use your currency. You can retrieve hourly the exchange rates (from yahoo) and store every single expence converted in the currency you want. There are categories and simple money converter, and many more! You can search in the balance for what expence you have in a determined category or in a determined period. It's useful and cheap!