I'm not used to get anything free in life, so just wondering, is the bonus real or virtual. Ie are you able to withdraw the bonus, or is it like "free spins" some virtual credit you have to spend on the site?
Which bonus you are asking about? You ask like this sounds like a general question which may have many different possible answers so you should be more specific when it comes to bonus.
As of now you did not mention which bonus you are asking about, I doubt there will be someone who can answer you correctly as different bonus may have different rules or terms.
Better for you to visit the bonus terms page of the bonus you want to know as I believe every casino provide the details of the bonus that you can read yourself.