I have made a duplicate content of my webiste, so I can just send paid vistors to it, like PPC and etc.
Will that effect my other website which has high rank?
If you have the mirror site in a folder that is not linked from any part of the site it won´t be indexed unless it receives some external BL, which doesn´t seem too likely. But yes, to be sure put a robots.txt and block the bots.