You can own these credits by purchasing them. This purchase can be made via your PayPal or credit cards. In short your Facebook Credits can be purchased via real currency which is transferred online.
If you wish to know how much Facebook Credit you have or your balance, go to your 'Payments' Tab via your Account Settings. You can buy your Facebook Credits from this same tab of 'Payments'.
Facebook Credits were first introduced in alpha stage during May 2009. After this, in February 2010, the beta stage was brought in which lasted till January 2011. Facebook Credits have grown in size and popularity.
Do you use Facebook Credits? Share your experience here.
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