For those expressing concern over not knowing the graduate well, and in turn don’t know if you should go to the party or send a gift, remember but none of these are summons. You don’t have to attend a party of someone you don’t know well, and you don’t have to send a gift for someone who you don’t know well.
I usually give $50 for kids of friends or kids of cousins etc. I gave my niece $100. I gave her boyfriend $25 because I don't know him well. My kids are graduating this year. I'll give their core group of friends each $50. I wouldn't take each invite or announcement as a request to send a gift/money. Yes, it's nice to receive to help them get started with their plans after high school, but for the most part these parents and students are just really excited and proud about this accomplishment and just want to share it with people. I wouldn't think too much on it and over analyze it.