The most significant outgoing is on food. According to a recent Mintel survey, the average weekly spending on food by a family is £85.
But for the benefits claimant Denise Ellerman, 51 from Stoke-on-Trent, the food bill still accounts for the majority of her weekly budget. She said the "bedroom tax" will see her income after rent and council tax fall to £57 – only £4 more than Iain Duncan Smith's notional £53-per-week.
She can afford to spend £35 per week on food for her and her daughter, a student who lives at home. On that sort of budget, many have carefully to plan what they buy.
Another claimant, Neil James, who budgets to spend £71 a week in total, said he is careful to buy plenty of cheap carbohydrates with each shop.
Wendy O'Brien, who lives on £65 per week, agreed that she can only afford the most basic of foods.
"I haven't bought fresh meat, chicken or fish for many months," she said. "I have a supermarket very close to my home so I pop round every evening at around 6pm, when they've made all the date-expired reductions.
"We have a local church that provides food parcels but I just can't bring myself to do it."
Nearly 20 per cent of British households are in fuel poverty, with Britain bottom of Europe's league table, according to a report by the Association for the Conservation of Energy and the Energy Bill Revolution campaign.
The combined cost of electricity, gas and water to Denise Ellerman is £14 per week. That, she said, means she can afford to heat her house for around two hours each day. The cold snap means that heating bills are hitting many households harder than they did at this stage in previous years.
Mr James, who earned £32,000 a year before losing his job as a lecturer when he fell ill, talked of his fear at having to "permanently turn off the heating" in order to make ends meet. Wendy O'Brien meanwhile spends around £7 per week on water.
The 'out of bounds' extras
What some benefits claimants said they could not afford:
* Repairs to or replacements of household appliances, eg a broken washing machine
* Mobile telephone
* Internet access
* A car and, in some cases, public transport
* Socialising away from the home