Just because you have already claimed your welcome bonus, it does not mean that you will not be eligible to receive more free spins in the future.
Casino websites are not just about attracting new players, they know they have to keep their existing customer base happy in every market or they will lose them to rival websites.
This is why you can expect to receive regular bonuses and promotions from a casino, often with free spins to enjoy.
These can be offered as a reward for another deposit, for playing a certain amount of spins on a game, or just because the casino is feeling generous!
Either way, you should expect to have offers of many more free spins in the future.