In Colombia is a system of mobile, provided only if the user has balance. It is subjected to recharge your account to use it, otherwise only account with a line on your behalf. Before cards were used to recharge, it is today very easily in many locations. It has the advantage that if it is not needed or not used does not have to pay. Also says prepaid to a girl who exercise prostitution in a clandestine manner and contact you for a phone number, normally exerts its activity attempting to discover that not your family or friends, as well as making it intermittently have it. Public transportation card, which can be used dee be recharged and present available balance.
