One in four people fails to save any money at all and most who do use the cash for a holiday, a study suggests.
The amount Britons has hit its lowest level for half a century
The Post Office research indicated that a third of people did save, but not on a monthly basis.
Just over a quarter of those who did not save said they had too many debts to pay and a fifth simply spent it all.
Office for National Statistics figures released in June showed Britons were saving proportionately less of their income than at any time for 50 years.
Among those who did put cash aside the most common reason was to save for a holiday.
Nearly half of those aged 55 to 64 said they were saving to prepare better for retirement.
BBC economics editor Evan Davis said the figures were "not surprising" given the low interest rates of recent years and earlier ONS figures showing savings were at their lowest level since the 1950s.
In recent years central banks had used low interest rates in an effort to stimulate economic growth by encouraging people to spend, he argued.
"To some extent the economy has grown a lot and that's been dependent on us not saving," he said.
Now the banks were trying to encourage more savings through interest rate rises but he warned that low savings could lead to problems for consumers in future.
"In absolute terms, as we get richer we save more but our expectations rise, so in order to have pensions of 21st Century levels we probably need to be saving more than 2% of our disposable incomes," he added.