Basically, using a mobile phone in Spain without a contract can get pricey. It´s that simple. I learned a lot by looking at what the young people here do to save money. Text messages, text messages, text messages! They can be a pain to write but they are really cheap. There is also an option on some phones to, instead of send a regular message, "chat" even though you get charged for each message you send, it is cheaper than just one normal message (you also can´t write as much, but still a good amount). Also if you just need to tell someone that you´re downstairs waiting for them or some simple thing like that, don´t call them, give them a missed call,a "llamada perdida". Just let it ring once and hang up, you don´t get charged unless the other end picks up the phone. Due to the prices of mobile calls, people on a budget in Spain don´t usually spend that much time on their mobiles just "chatting". I guess if you were calling local non-mobile numbers in madrid, a phone card and a telephone booth would be your best bet. Just to make sure, you know that calling a mobile phone number is more expensive than calling a regular number?