I was explaining to someone from Ireland how American university admissions work, and I was embarrassed to have to admit that rich parents could buy their kids places with big donations. It seems even seedier when you explain it to someone from another country.
Note that the most selective American institution of higher learning is the Curtis Institute, which has never charged tuition. Note, too, that all admissions decisions there are made by faculty juries; Curtis has no department of admissions. No one buys his way into Curtis.