Microsoft points are a form of digital currency created by Microsoft for use in the Xbox Live Marketplace and Zune Marketplace. Microsoft points are different from Gamerscore in that you must actually purchase Microsoft points by charging them to a credit card or buying redeemable points cards available in many retail stores. Microsoft uses the symbol .
Microsoft points do not have a set standard conversion rate. Although similarly priced around the world, Microsoft points convert in America 80 points to 1 U.S. dollar. Downloadable games, and downloadable content, are generally available in multiples of this 80 point standard. 400, 800, 1200, 1600 point values are common when purchasing downloadable content or arcade games. Again, in the US dollars this would equal approximately 5, 10, 15, or $20.
To add Microsoft points to your Xbox live account, you may purchase a points card at a retailer or an online outlet such as Amazon.com, or you can enter a credit card into your Windows Live ID and Add Points through Xbox.com from the right hand side of your My Account page.
Rumors, and recent pricing changes on systems like Windows Phone 7 and Games For Windows Live Marketplaces, indicate that Microsoft may be moving away from their Microsoft points in favor of standard, localized government currencies, but no transition date has been officially announced. Until then, we will continue to use Microsoft points to make our purchases on Xbox Live Arcade and the Xbox Marketplace.