Slot-Machines are all set up, it chooses when it's going to give the prize, lets say theres a circle, and one tiny dot all the way up of it, It goes round and round as people play it, until the dot goes back to its original spot is when they win the jackpot. So it's not random at all.
Exactly what this guy is saying, proven a long time ago that slotmachines are rigged and will give out the prize only if the income has been more than the prize itself.
Slot Machines are not worth it - you have the biggest chance of losing money there. Roulette is based on luck, the house edge is 5.26% so you have the highest winning chance on color 46.37%. This is based on luck and it doesn't require your decision except when you place your bet. Blackjack is a game which requires your decision and if you get a 21 when the dealer gives you 2 cards and he doesn't get 21 as well, you'll get more than 2x (I am not sure how much is that anyway).
This game requires your decisions and you may regret if you hit\stick very often but there's a higher chance to win on this than on roulette. Anyway, I don't recommend trying casinos because you may win and after you won't stop even if you don't wish that, you'll want to get more and more and you'll lose it all. Sports betting is better.