The invention relates to a method for using an application (18) in a mobile station (1). The application has a first mode of operation and a second mode of operation, whereby the first mode of operation is passive, and in the second mode of operation the application controls the master control unit (MCU) of the mobile station. The invention also relates to a system for making payments, comprising at least one mobile station (1), which has an application (18), means for using the application (18), and the first means of data transfer (IR, 20, RF) for local data transfer. The system also comprises at least one cash register (21) or the like, which has the second means for data transfer (IR2), and the application (18) comprises means for transferring data between the first means for data transfer (IR) and the second means for data transfer (IR2).