1. If you just want to put a few coins in and play for fun it's fine and who knows... you may be a lucky winner.
2. Most slot machines guarentee 70 - 80% payout on average - this means that the slot machine ALWAYS wins 20 - 30% of everything people put in over a period of time.
3. You can reduce these odds and increase your winnings legally in various ways if you are more serious.
I can give a few tips if anyone is interested.

Oh that are great tips you have shared with us here.
Could you please post some more? I am eager to know about the slot machine mechanics.

Just a few tips here now:

1. Watch just 2 or 3 machines carefully. Learn them a little bit.. how the reels and symbols fall, believe it or not there IS a pattern.

2. Let other people put the money in trying to win. Watch them and learn from their mistakes.

3. When enough people have put enough money in without winning much then the machines are getting full of money and have to pay out 70 - 80% at sometime soon.

4. Then it is YOUR turn to go on these machines. They are ready to pay out. Be prepared to invest a few dollars and don't get too greedy when you win... DON'T keep gambling and trying to 'double' the money.

5. Collect your winnings and walk away. DON'T be tempted to re-invest in another machine which you know nothing about.

Enough for now... hope this is useful info. for you.

I knew there had to be some sort of trick or mechanism to increase your winning or payout possibilities Thank you for the info youngfellamelad.