I am close to my niece, and I have no idea what is considered"average" for a college graduation monetary gift

It all depends on what you can afford. I don't think that there is anything as some sort of "average" concerning this. If it were me giving the gift, I think that $100.00 would be sufficient. For others giving monetary gifts, it might be more or less than that.

Yes, do you make 1 million a year or do you work a min wage job at Walmart. I seldom give more than 50 dollars personally but then I friends that 250 to 500 is not uncommom as gifts. In the end it will depend on your ability and also if you have other nices or newphews are you going to set a pattern or make others mad latter for not being treated the same