If your computer has a wi-fi adapter, you can turn it on and using search networks to search for those networks that are open or are in open access. If you can find the network, try to connect to them, and if you succeed, then you can use them indefinitely. The most important thing here – caution, do not put large files for download, if you do not want one on that network has a password.
You can use the above method to connect to the Internet in public places such as restaurants, cafes and hypermarkets. To connect similar to the previous step, use the wi-fi adapter. If the network is unprotected, then just connect, and if protected, contact a service personnel to know the password and login access.
You can also use the stock providers that are similar to each other providing first thirty seconds connection for free. The most convenient way is to use a special program-"dialer", which will call up the operator, and on the last second to drop the connection and call again.