First, you have to make sure you only have little GoCredit (100 GoCredits and below) in your account but enough airtime on your phone or data bundle, this means that if you are on a data bundle then you don't need to worry about having enough airtime on your phone. Go to Settings » Change Style, locate any style you want and press the save option, It will show downloading. After downloading the style, you will get an Error Message that You don't have enough GoCredit to Buy the Style. The style will apply or go back and click on "My Styles" on the Style Menu. You will see the style there.