State schools are asking parents to hand over cash for everything from books and tablets to building projects, according to a poll.
It suggests that the vast majority of parents (95.8%) have been asked to contribute money to their child's school.
Of those that had been asked for money, nearly half (45.3%) had been asked between two and five times in a year and a third (32.2%) had been asked between five and 10 times.
Netmums, the parenting website which commissioned the survey, claimed that families are spending an average of £200 a year in donations and additional costs off each child educated at a state school.
This figure is based on a Netmums analysis of the figures showing that mother and fathers spent an average of £100 a year on direct donations to their child's school for items such as sponsorship for charity events and new building projects and a further £100 on average on costs such as costumes for school plays, text books and uniforms.
The survey findings show that more than nine in 10 parents (91.2%) were asked to pay for day trips and school outings, while a third of those questioned (34%) said they had been asked for money for swimming lessons.
Around 16.5% of those surveyed said their school had asked them to help pay for new building projects, the poll claims, and a similar proportion (16.4%) had been asked for donations towards the upkeep of buildings.
Parents had also been asked for money for items including goods that children had designed, like tea towels and cards, fundraising events and residential trips.
Just over one in four (28.2%) of the state school parents questioned said that they struggle to afford the extra costs and have had to cut back in other areas while a further 6.5% said that they cannot afford it and their child had missed out on something.
Netmums co-founder Siobhan Freegard said: "State schools are certainly not free, as parents are paying out hundreds of pounds a year each to support them.
"Parents around the UK are doing their very best to prop up falling budgets but with many more mums out at work and overstretched family finances many simply don't have the time or the money to do all they would like."
:: The poll questioned 1,577 parents including 1,337 with children at state school in February.