Mobile users have the option to make online purchases via the carrier. Depending on the mobile carrier, there are different billing methods at the disposal of the user. One of the most frequently used methods is the MT Flow. This billing system enables the mobile users to finalize the online purchases in just a few easy steps. The user has to provide the merchant with their mobile phone number, after which theyll receive an SMS containing a PIN code. The user will have to submit the code in order to confirm the ownership of the phone number in question. When done, the purchase will be finished.