The answer is that prices range from anywhere from $500 toR$25,000. You might be thinking that it is a lot of money to own a slot machine, but when you think about all of the money that these machines make casinos every year, you will realize that they pay for themselves.
In reality: Put in an amount you are willing to lose. You're more likely to lose it all (or much of it) before you decide to move on. It depends on what kind of player you are. I know many people that just play for fun, and are perfectly happy just dropping in aR$20 and playing a machine until it's gone.