Just how expensive is it to visit south korea for a couple of weeks?

From america, I am planning on going to south korea for a couple of weeks.. After the plane ticket and considering I dont have to pay for lodging (I have friends places I can stay at as well as couchsurfing), what will it cost me to obtain food and necessities? I hear a meal is $3-5 but what exactly is included in that meal?

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia��).