Cost of living: Cambridgeshire families scared of rising prices
A charity that helps families said people had been coming to staff worried about how they would cope this winter with rising prices.
Peterborough-based Family Voice said many would be at "crisis point" and it said it was also concerned about its own finances.
Chief executive Louise Ravenscroft said she was "dreading" winter.
Treasury officials said decisions on major fiscal issues would be addressed after the new PM takes office.
Many families are already facing soaring costs, with UK inflation - the rate at which prices are rising - at the highest in 40 years.
People have also been warned of sharp rises in energy prices, with average bills forecast to reach £4,200 in 2023.
Ms Ravenscroft said: "I don't know how we're going to cope when we have to have the centre open in the winter - the bills are going to go through the roof."
She said the charity's energy bills had already increased by 200% since April and other bills had also risen.
"We're going to see far more families reach crisis point," she said.
"It's going to be very scary, we're already seeing families struggling."
Kelly Hodgson, a mother and teacher who only has electricity in her home, told the BBC her energy bill had gone up from £90 to £250 a month.
"We're not going to be able to afford holidays, days out. We're not going to be able to afford extra treats, clothes, things like that," she said.
Richard Murphy, from Ely, who is a professor of accounting practice at Sheffield University, said: "There is nothing about what is coming our way that is sustainable."
He said everyone, whatever they earned, would notice a £3,000 increase in their fuel bills.
"Everything is going up, people will literally reach the point where they cannot pay their bills," he said.
Conservative leadership candidate Rishi Sunak said he would provide more money to help people with their energy bills, if he became prime minister.
His rival for the leadership, Liz Truss, has pledged tax cuts to help people hit by the cost of living increases.
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