This really depends on the stage of player you are in. If you are joining a new online casino you could receive a no deposit bonus as a welcome bonus. If you are a existing player, the casino could give you a no deposit bonus on a specific game so you can try it. If you haven't played in a while, the casino could offer you the bonus to get you back to their casino.
No Deposit Bonus Guide
These are arguably popular bonuses in the world of online casinos and there are some very popular no deposit bonus offers available for players which are often in the form of a welcome bonus casino offer. While these have become rarer to find in recent years, a lot of new online casinos usually offer this alongside a deposit bonus offer as well.
It effectively means that you can start playing straight away once you claim your bonus because you do not have to make a deposit in order to receive it.
These free no deposit bonus offers can vary in terms of the amount of money that is on offer for new customers and usually you will find that t&c's apply (terms and conditions) so it is definitely worth checking these first to make sure you understand what is required.