I can only speak from our own slightly dated experience. $3-15,000 seemed “normal”. But one poster here has been offered $40,000 at a girls school.
I think it really depends on the school and how they use FA and merit. There are definitely different philosophies around it and it really varies depending on what demographic the school hopes to yield as a result. Some try to boost stats by offering it to really high achieving students, some use it to improve their teams, and others do it with the hope of getting more families who can contribute to tuition but might not want to write a check for all of it. In each of those cases, who gets it (and the # of recipients) and how much differs.
I would guess if the school has only 5 (that’s really about 1 per grade), it should be on the high side.