Google is making the practice of sending money to friends as easy as attaching a document to an email. Using Gmail, you'll be able to attach cash money to your emails using your Google Wallet account, for free. The nice thing is that you don't have to have funds on your account to do this--you can just have a bank account attached to your Wallet account. Recipients of your paper won't need to have a Gmail account, which is one more thing you don't need to worry about, and anyone you send money to can return it to you as well. Google is rolling out the feature now to Gmail users over the age of 18. Check out a video that explains it all, after the break.