So some thought about this, as I used to be regular of a local casino, not because I felt I had to go, just to play with cash vouchers, they used to send, maybe occasionally putting in a 10 dollar bill or two. I didn't make money out of it, but I did not lose my own money. I guess when they realized they are not making money from me, they stopped sending me those vouchers... Bummer! :-)

Those machines are really designed to salami slice players. You can play many of those machines from a penny per line, which equates to about 15 to 30 cents per play for full lines, depending on a machine. There are people who play at higher stakes, like a max bet of $2 per play, or even $5, but observing people, majority seems to be played at much lower bet of a penny or two per line, so I'm guessing they consists of high fraction of profit a casino is making from.

It's fairly easy to lose a sense of spending when you are doing literally a thousand play per hour. (At 30 cents per play, You'd be spending fairly long time to spend $20, or even $10. At this level, a typical win would get you around $2 to $5, maybe $40 if you are quite lucky -- and perhaps real jackpot, being very, very rare, $200 or so.) Those "wins" really give you the joy that you'd anticipate for the next, and a lot of time, they'd put more money in just to anticipate another win, because when they have lost plenty of money, it's about a time they will start winning, right?

Knowing someone who really got into it, one sign I started seeing from them is that they'd start making a statement like "I'm not playing it for money, I play it because the game is fun." He would play the game literally for hours per session, often visiting there multiple times a week. Usually ends up losing -- maybe the only good thing is that he'd have accumulated quite a bit of free restaurant credits.

So if you are inclined to play, here's some suggestions, though for those people who would feel these suggestions are useful probably find the best is not to play at all:

1) Set a budget -- don't bring extra money. (And don't bring ATM card/credit card if you feel like you can't resist getting extra money out of them...)

2) Record every win/lose -- I've had Google Doc that keeps track of every wins/lose every machine. Every time I cash in, I'd record, every time I cash out, I also record that, that would give me balance sheet how much I'm spending/making.

3) Bet generously -- Don't bet a penny per line, go higher. You won't go anywhere with such low bet anyways. You'll have a better chance getting a better outcome going through that $20 in 2 minutes than spending 2 hours on it. Yeah, it may only last 2 minutes, but then you have good reason (See #1) to leave at that point -- and you are giving less chance for a machine to alter your psychology.