First-time buyers save an average of £27,000 when they move from being renters to homeowners, according to research by Halifax.
The amount of money they save over the lifetime of a 30-year mortgage is almost as much as the average deposit, which is currently £31,751.
The latest Halifax Buying versus Renting Review found the average cost including mortgage payments of buying a three-bed home in the UK was £679 a month in December 2017, compared to the average monthly rent of £754 for the same property type.
The gap between the cost of buying and renting is now at its highest in four years, up 44 per cent from last year's £623 saving to £900 a year.
Russell Galley, managing director of Halifax, said: "The gap between buying and renting has widened significantly, primarily driven by a reduction in mortgage rates and a more competitive market pushing down monthly payments.
"Meanwhile, the cost of rent, household maintenance and average deposits have remained broadly flat.
"Despite having to put down a sizeable deposit up front, homeowners are overall better off than renters in all parts of the UK. But those who are unable to get onto the property ladder because they can't raise enough cash are paying more by renting.
"The good news is that record numbers of first-time buyers are still taking their first step on to the ladder and helping to bridge this gap thanks to a continued low-rate environment and government schemes including Help to Buy."
Those who live in London save the most when they become homeowners, paying an average of £183 less a month, while those who live in Yorkshire save the least, with a monthly difference of just £49 between buying and renting.
The number of first-time buyers fell from a high of 359,900 in 2007 to an all-time low of 192,300 in 2008, according to UK Finance.
The levels are back to the pre-crisis peak, having reached 365,000 in 2017 and exceeding 300,000 for the fourth consecutive year.