While some Android users, like T-Mobile in the U.S., have had the carrier billing option available for a while now, many other carriers globally have not had this option available and are forced to use options like Google Checkout every time they need to pay for an app. This is about to change within the month due to a change in the Android Market Developer Distribution Agreement.
While the free apps have long been the big upside to the Android Market (about 57% of the apps in the Android Market are free currently), with the number of paid apps rising it's nice to have the options to lump all of your apps into your statement instead of running through all those clicks to spend 99 cents and such. Just make sure you don't pick up so many that you end up with mobile bill shock.
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