You can find your Payment Settings here:
- Click the button with a gear depicted at the upper right corner and choose Settings.
- In the General Account Settings menu find Payments at the left corner of the window.
The following data can be viewed in Payments Settings:
- your current balance;
- subscriptions (an opportunity to set recurring payments);
- purchase history;
The following settings can be edited:
- payment methods (an opportunity to save the most frequently used methods and choose a preferred one);
- preferred currency (an opportunity to change the local currency that will be shown and puchased as);
- shipping addresses.
More details on Facebook payments can be found here.