What should be communicated by the existence of a disabled button, if it is more features in your application that you can purchase or easily access by doing some action then show it. If it is something you just cannot do and will not be allowed to do in the current situation for some reason then don't show it.<p>When you show it animate its appearance the first time.<p>If your user has given you money that will allow the disabled functionality to be enabled give them the opportunity of visiting a page where they can see all the neat new options they purchased.