It is hard to give the right answer as poker rooms treat people from different countries differently.
I live in UK and have a lot of bonuses from UK sites as the competition is tough here.
On the other hand the sites like Betonline have an exciting offer for Americans
but only for them. Also 888 gives different amount of bonus depending on your location.
if you dont have a lot of different accounts look on sports side most got 150 dollar first time deposits bonus - most will let you transfer money to poker side if they got one. of course many of them are considerable smaller poker rooms but general easier to win in
You just need to search on websites belong to poker rooms, they usualy have tab PROMOTIONS or something like that and there is everything wroten.
Search many different sites and find what you need
Each poker room offers a first deposit bonus and some have freerolls for beginners. It's best to start with no deposit getting cash from Pokerstrategy, for example. https://www.pokerstrategy.com/
I recommend you search on google. Generally, users in the United Kingdom enjoy the most bonuses in most poker rooms. Don't ask me why. However, all rooms have a deposit bonus, but if you are looking for bonuses without a deposit, it is more complex