A method and system for automatically placing calls made from a mobile telephone in an economical manner via calling card and call-back programs, with minimal user overhead. The system may be installed on an existing telephone by the user. To operate, the user initiates the placement of a call in the regular manner, as if the call were placed directly, and the system automatically places the call in the most economical way, such as via calling card or call-back program. The user can employ any dialing conveniences offered by the mobile telephone, including “speed dialing”, “phone book” dialing, or recent call dialing. All interaction with the calling card/call-back server is handled automatically; the user need not be aware that the call is being placed via a calling card or call-back program. Additional automatic features include automatic calling card recharging and selection of SIM for telephones supporting multiple SIM's.