You can find a mobile phone number for free using social networks, which are essential sources of information at present. First, try to find personal page the right person in one of the social networks. Because of these resources quite a lot, try typing his name into any major search engine of the Internet. As a result, you will be able to find a link to their profile in a particular social network.
Read the information about the person. Often people leave their phones for communication. If the number in the profile is not specified, try to contact the user's friends and under any pretext to know the number of his mobile phone. Also, pay attention to all kinds of groups and public pages, especially in the city, where lives the man. They often have special sections where you can ask a question about a particular person. It is possible that the group will be someone from friends, who will tell you the necessary information
Remember all of the information that you are aware about the person like where he lives and works, whether your site was not published any information about it in the public domain. If you know of any details, try to find a mobile phone number for free via Internet search engines. Putting in the search string the site name of the person, his place of work or just the name, you will be able with high probability to find his number on the Internet.
Contact cell phone stores in your town. Usually information on customer numbers, operators do not provide, however, if you persistently ask, or you just get lucky, you will be given the necessary information.
Visit places in the city, where usually the man, for example, his place of study or work. Of course, it is not necessary to follow him and follow you, but if you saw it, for example coming from a public institution, you can ask the staff who the person is and what his room. You can think of a reason why you need to find out, for example, you found him lost thing that you want to return personally. But the efficiency of this method largely depends on luck and your talent to convince people.