Graduations are one of the few occasions for which I am comfortable giving money. Nothing says “thinking of you” to an 18 year old like a check. But it’s been a while since I’ve received a high school graduation announcement, and more years than I like to think about since I sent high school graduation announcements. So what’s the going rate these days? The graduand in question is the bright and sweet daughter of my first cousin. I see her, say, five to six times a year on family occasions. How much should I give her?
Whatever you’re comfy with. Regardless, it’ll be more than you can afford and less than they want.
Yes, well, what I’m comfy with is an amount less than that which would cause her to burst into tears of joy and more than that which would cause her (and her mother) to think I’m cheap. What I’m comfy with is the expected amount. I’m sure that’s a range, but I don’t know what the range is anymore. (I’m old, ooooollldddd . . .) So I turn to the Teeming Millions, who know everything. 
I think a couple years ago most people gave me $20. Some less, like $5 or $10 (usually people I hadn’t seen in a long time), some more (all family, I think). I kept track of it all (for the thank you notes) in a notebook, but I don’t know where that went.
$20-$25 is about what we’ll give for a graduate who is either a relative or the child of a close friend. Haven’t heard any sniping behind our backs yet.
We gave $50 to my son’s best friend. I would think $20 to $25 would be fine.