Well you better be strong willed and ensure you follow a plan. Say you're going to Vegas for the weekend and you want your money to last the entirety of your stay. Keep that smile people, you're supposed to be having FUN! Trust your instinct because if you don't, you'll hate yourself for it later and you'll get in a sour mood. After 10 spins, re-evaluate if you want to keep spinning or continue playing. Perhaps get yourself 10 $5 bills and pick out 10 games to play. It may sound small, but that's only 100 spins and that may not be enough to even land a bonus. If that's your prerogative, go for it! However if you have $50, then keep to those 50cent spins or under. Don't get me wrong, I have friends who have played on $20 for an hour betting 8 cents a spin. I have lost $50 in a single spin many times, haha. $50 is not a lot of money, especially when you're considering using it to gamble with and potentially lose. Regardless, let me entertain that notion. Personally, it takes me 90 minutes to get to my 'local' casino, one way! So I won't be making that drive with a $50 budget as it would cost that much to get there in gas, haha. The simple answer is that it should be whatever you're comfortable losing! So let's say you only have $500 for a weekend or $50 for a day.
People often ask me what their budget should be for the casino.