Every casino gaming theme has a special feature known as free bonus slots. The gaming machine only allows the gamer to play the free bonus slots when specific symbols of a winning combination appear.
There are many types of free bonus slots as each type of game has its own unique set. However, in most cases, the free bonuses are a special session. A gamer can get several of these special sessions depending on the number of winning combinations he or she gets. Ideally each winning combination corresponds to a free bonus game.
In some games, a gamer is given a chance to select from a number of items. Each of the items is valued differently so the gamer must be careful o chose only those that will be beneficial to him or her in the game.
Credits are also awarded during the game. These are openly displayed and the gamer has to use them to know the credits gained or lost as the game progresses. Since it is a game of probability there is no guarantee that a particular item will return the same value of credits next time it is chosen.
Most of the free bonus slots nowadays are automated and very few are mechanical.