"Free" spins bonuses are becoming an increasingly popular form of bonus offer. They are often given as an additional extra which is awarded on top of a normal deposit bonus. So for example, you might deposit $100 and receive another $100 in bonus money, and the casino will throw in 50 bonus spins on one of their slot machines. The spins are set to a specific coin value which is fixed until all your spins are completed.
It is important to read the terms on these offers because, as is usual with casino bonuses, "free" is rarely free. Sometimes the winnings from the spins are paid straight into your cash balance, but more often than not they are treated as an extra bonus credit with the associated wagering requirements attached that you must complete before withdrawing.
Casino bonuses which include free spins
Note for U.S. players: unfortunately most of the free spins bonuses are offered by casinos that currently do not accept new players from the USA. If you are looking for some free casino offers check out our no deposit bonuses page, or you can find a massive list of slots bonuses here.