There are lots of small casinos I've come across offering bonuses or free spins upon registration. But you must know that you to claims such reward requires you to play or wager some amount in their casino. There's no guarantee that will be able to cash out such lucky spins without depositing. Just as @Oshosondy has said most of such sites are either scams or not legit so be sure to make some research firsts about them before depositing.