How much money is appropriate to give as a gift for high school graduation?
Well, a gift is only a gift if it is freely given–not imposed upon you (and that includes the price). You give what you can afford and what feels right, keeping in mind that if you give one of the sisters X amount, you’ll have to give that same amount to the next sister and the next sister since you know them all. Teachers salaries aren’t huge and the kids know this–would probably feel bad if you gave them a lot of money. $20-$30 would be reasonable, especially since you are not related to them–and it’s more then they had before.