Parents are a growing source of extra cash for state schools, particularly in wealthy suburban areas where they help mount sophisticated fund-raising drives.
Parents from Malibu to New York's Greenwich Village have been spearheading efforts to raise tens of thousands of dollars to pay for after-school sports or art classes or pay for building repairs and computer centres.
In the past 10 years a tight rein has restricted education spending across the US. Though the bright economy and the new political focus on education have begun to loosen the purse-strings, many schools pursue outside revenue. Parents at one 400-pupil school in northern California contribute more than $1 million (Pounds 600,000) a year to its funds.
Jay Butler, of the National School Boards Association in Virginia, said:
"We have seen a tremendous emphasis on fund-raising over the past five years. It is happening because there is an explosion of needs in the schools."
Wealthy Greenwich Village parents recently raised $46,000 (Pounds 29,000) in a matter of days after learning that a popular staff member had been laid off in budget cuts. School officials first refused to accept the money for the teacher's salary, but then changed their minds.
Parental fund-raising can raise the sensitive issue of equality in education. The Santa Monica school district in California, for instance, runs impoverished inner-city schools in the Los Angeles basin as well as Malibu high school in the coastal enclave favoured by the movie industry elite. "They all do fund-raising, but it reflects the socio-economic status of parents in the community," said a district spokeswoman.
The San Jose school district in Silicon Valley stretches 25 miles, and includes the poor and heavily minority areas of San Jose city and the pricey suburban homes of the computer industry's new rich. The district runs centralised fund-raising efforts which include the annual Celebrity Waiter luncheon, where local sports stars wait on tables for which local businesses pay hefty prices. The event has raised more than $100,000 in each of the past five years, funding sports and more recently music programmes. But "home-school" clubs offer parents the chance to contribute directly to their own child's school.
Sponsored walkathons in some elementary schools have raised up to $70, 000. IBM and other local companies have now begun offering matching grants to equal gifts that employees give to schools.
School officials say they try to iron out some of the inequalities with government grants for communities in very poor areas or with large non-English speaking minorities. But there is still a huge gap in amenities between suburban schools with new computer laboratories, and city schools with wire-fenced playgrounds.
"The schools are not funded any differently, but it looks like two different worlds. It's a horrible dilemma," said Maureen Munroe, a spokeswoman for San Jose schools.