We are moving towards Open Office Culture and want to use the Libre office. can we use the same without paying anything
Sure it’s free for commercial use. However you are encouraged to donate and to involve in promoting the culture around so it will grow better and free for every one
Yes. LO is free for use by everybody. From the readme page (which is currently based on the text file distributed with v4.3):
LibreOffice is free for use by everybody. You may take this copy of LibreOffice and install it on as many computers as you like, and use it for any purpose you like (including commercial, government, public administration and educational use).