Tipping in iOS is now done using Peeks Social Coins.
You can buy coins on mii.tv website.
To purchase coins, please login to the mii.tv website and click on the “Get Coins” button on the home page. Please select the coin package and PayPal or CCBill as the Method of Payment (in the drop down menu). The page will connect to PayPal/CCBill to process your coin purchase.
If you are not able to purchase coins or experience any errors/issues, please contact mii.tv customer service at support@mii.tv.