Pelham, until it ran out of room, accepted outsiders, requiring them to pay a tuition pegged to per-pupil cost.

Meanwhile, New Jersey's per-pupil costs, more than $10,000 a year, are the highest in the nation.

Charter schools are public schools financed by a percentage of the per-pupil costs from the district that a child leaves.

Salaries and other costs raised the per-pupil cost to $8,439 in 1989-90, the highest in the nation, according to the National Education Association.

An incoming student with $2,000, coming into a district whose per-pupil cost may range from $8,000 to $9,500, does not support a revenue flow.

It now spends $45 million a year, for a per-pupil cost of more than $8,500.

Because the state pays the room, board and textbook fees of each student, the per-pupil cost of $10,000 is high.

Its officers say the company must now expand, by adding more schools, to gain economies of scale that will reduce the per-pupil cost of bureaucracy.

The other reason New Suffolk can afford the high per-pupil cost is the small number of students in the hamlet relative to its total tax base.

The goal, he said, is to reach the state average per-pupil cost within four years.