A commercial interface (SBB) is provide in each Internet access network (IN-AN) for carrying out cashless payments. When a mobile communication terminal (KE) asks for a link to be established, a traffic relationship is established towards the commercial interface (SBB). After a cashless payment has been made using the commercial interface (SBB), the Internet access network (IN-AN) can be used by the mobile communication terminal (KE). This method provides for an improved flexibility of use of the Internet access network (IN-AN).