The cost of residential care for vulnerable children in England has nearly doubled in five years but many children still do not receive appropriate care, says a report from the independent public spending watchdog.
The National Audit Office (NAO) says councils on average spent £318,400 on each child placed in a children's home in the year ending March 2024.
But these huge sums do not represent value for money, the report concludes.
"I do not know where the money is being spent," says Ezra Quentin, now 20, who recalls smashed windows and broken glass in the showers of one of the care homes he was placed in.
Ezra, who now works with Become, a care leavers' charity, first went into care aged nine.
Originally from Greater Manchester, he remembers being moved to a different home every few months, often many miles from where he originally lived.
He thinks he had up to 60 different placements and although he has spent most of his life in Salford and Stockport, he has lived in Wales, Liverpool, Crewe and Leeds.
His education was considerably disrupted but he did achieve C grades in all of his GCSEs.
At one home the windows were boarded up because of smashed windows.
"We were told to wear shoes if we wanted to shower because they didn't clean up the glass properly," he told BBC News.
The NAO report found rising costs were driven by a record number of children in care, the increasing complexity of their needs - and a profit driven market.
In 2023-24 councils spent £3.1bn on residential placements, in a market the report describes as "dysfunctional".
It says councils are struggling to find enough appropriate placements, arguing that this allows many private care providers to cherry pick the children they take, based on how much support they need and how much profit this allows.
The report draws on previous research which showed the 15 largest providers of children's homes making average profits of more than 22%.
Report author Emma Wilson says several factors contribute to rising costs but with the overwhelming majority (84%) of children's homes run for profit: "It's really important to get right that balance between supply of available care home places and demand."