It depends on the OPs situation - so it could be very inexpensive - depends on the student’s family.
In the last CDS, of 1099 first years, 596 were given a grant or 54%. So near half were full pay.
The average grant was $67,740.
Direct costs are about $86K - so on average let’s say kids paid about $18K.
But of course, kids aren’t average. Some grants would be full COA and others $20K so each student will need to run the NPC to see where they are.