I’m not familiar with academic social norms or the specifics of endowments, so take this with a grain of salt. If I was making 70k and was asked to donate to a fund like this, my gut feeling would be in the mid-low three figures, say $250 to $400. $100 feels a little scanty, anything over $500 would feel like going above and beyond. Once you’re nearing 1% of gross salary, that’s getting to where you’d feel the pinch. On the top end, I feel like someone making 200k could give $1000 to $1500.
So, if you had 25 people, let’s say the average gift is $700, that’s $17,500. Feels like a hefty chunk of money, but as the other poster mentioned, if you’re only taking 3-4% a year, that’s $5-600 ish. That’d definitely make a difference to your typical student, but it does seem like small potatoes for the university to administrate.