There are no special rules for playing the free online slot machines. The only difference between these free online slot machines and the paid slot machines is that the free ones do not pay back any winning money. But this should not pose any problems to people playing this type of free slots machines.
After all, the players are not investing any money to play the free online slot machines, so they should not mind if the machine does not pay back any cash winnings to them. Rather they should be grateful to these online machines for providing them an opportunity to hone their slot gaming skills. If you have not played them till now, play the free online slot machines today.