How to edit PDF files with free software

..Sir, I want to edit PDF files but if I search google for pdf editor then its is showing very costly adobe pdf XI to edit it. Do we have any free software available to edit pdf file ? I need to edit pdf files 2-3 times a month so there is no heavy use so I don't want to spend so much money . Want it free if possible.

I also checked online, I don't want online pdf editor at all.

Please tell me solution.

Manoj, PDF files are not meant to be edit. Some can be edited if they are made to edit but generally not. Still there are online site like escapepdf which allows you to edit pdf docs. Best solution is to modify original file and then export pdf.