These are a huge craze in casino's and have now hit the online casino's too. These are the slot machines where the jackpot rises every time someone inserts a coin and plays. These pay out the most money so have a play if you feel lucky today :D. These machines have a paytable and the prizes change depending on what your bet is. Your bet is usually 1 to 5. So say for instance if you got 3 cherries on the win line and you had bet 5. Lets say the prize for cherries is X12 so you would have won 60, but if you had bet only 1 then you would of won 12. Sometimes, you need to bet the full amount for a chance to win the jackpot, it all depends on the group of machines you are partaking in. You really need to figure out the best option for you when you arrive at the machine, instead of putting your money in right away and pressing the button, take a few minutes and think about what will be best option to suit you. And you can always change the bet whilst your playing so if the bet doesn't suit you then you can have a fiddle about with it.