This free Android app was the first to offer users a flatter wallet by storing credit cards on a mobile device, and has since expanded to other forms of payment. To use a card, tap the Android phone to a payment terminal when you check out at a retail store. You can use any of your stored cards for payment. Supported cards are Visa, MasterCard, American Express and Discover, gift cards and rewards cards. Google Offers
are also accessible, which helps you save money while you're shopping or trying to choose a restaurant or other merchant.
While Google Wallet offers a huge convenience, security is a concern. You'll need to enter a four digit PIN to use the app, and your mobile device can be disabled on the Google Wallet web site if it's lost. This apps is, of course, developed by Google.
One problem with this app is that not all stores have a terminal that works with Google Wallet. It's rumored that Google will be releasing a credit card that works with the app to overcome this limitation.