PPI stands for Pixels Per Inch. If you never put the pixels on something that can be measured by inches, then the number you put there literally doesn't matter, it doesn't change how many pixels the actual image has. What it changes is how big it will print on paper if you were to ever print it, a higher ppi means it's going to fit more of your image in a smaller space, lower means it's spread out and less sharp (though that also depends on how many ppi your printer can handle). 300 ppi is a fairly standard resolution, it prints well in most cases and is the resolution for a high end monitor.
I always told my DA fans how much I hate slot machines. They're fine in games as a risk-and-reward system. But when you're spending REAL MONEY in a Vegas casino to try and hit the jackpot (which very, very few people will), it can really hurt your budget. Gambling is a bad habit, and I don't like wasting my money on a slim chance. Go to Vegas for the experience, not the jackpot.