On the first morning of the first day after the ceasefire, the market of Asdaa camp, a sprawling area of tents and makeshift shelters on the central Gaza coast, was busy.

Some shoppers had come because prices of the small range of basic necessities available had dropped since the ceasefire was declared, making once prohibitively expensive items just about affordable.

Others came simply because they could now stand and talk and buy what they needed without fearing sudden death or mutilation.

Ahmad Al-Amarna, a 25-year-old stall holder, said he was happy because the ceasefire had brought “stability, lower prices and the end of the killings”.

“I am very happy that prices have dropped, and now people can buy things they had wished for but couldn’t afford before,” he said.

But if Sunday’s ceasefire has brought some relief, life for survivors of the war remains extremely hard. Health services have been decimated and swaths of the territory reduced to rubble. Water and fuel are scarce. Humanitarian officials have called for a “surge of aid” to stave off disease and potential famine.

Amarna said he and his family were suffering in the wintry conditions. “What we need now, especially with this cold and unpredictable weather, is blankets, clothes for the children and adults, and food, especially flour, at least at reasonable prices that we can afford,” he said.

Many in Asdaa camp, which occupies the site of a former funfair west of the central city of Deir al-Balah, celebrated the moment on Sunday when the ceasefire came into effect while standing in long queues at water points, food distributions or inadequate sanitation facilities.

Ghalia Sobeh, 54, had come to the market looking for rice for her eight children. “Until now, prices were very high, far beyond our means,” she said. “Many times we would go to bed without eating. Now the prices have come down a bit, but it is still very hard.”

“We have no source of income. We live on charity and aid. My children do not work, one of them is blind and my husband is elderly. He sometimes works, but it is not enough to support the family, so we mostly rely on aid.”

More than 630 humanitarian aid trucks entered Gaza on Sunday, the UN secretary general, António Guterres, told the security council on Monday. At least 300 went to the north of the territory, where the humanitarian crisis is most acute. The number of trucks reaching Gaza through Israeli-controlled checkpoints slumped in November to around 80a day, a fraction of the 500 or more which entered daily before the conflict.

A minimum of 600 aid trucks a day is specified in the ceasefire deal.

Many blamed a cartel of big traders who exploited the limited supplies reaching Gaza to push prices higher in recent months. A 25kg bag of flour now costs the equivalent of $40 (£33), a tenth of its highest price. The cost of instant noodles and cheese has dropped by a half. Fresh fruit and vegetables are also more widely available.

Abu Khaled Al-Muzaini, 50, a former businessman, said that for most people even with lower prices “the struggle remains immense”.

“The prolonged war has drained all resources,” he said. “I have been displaced five times. Others have been displaced ten times or even more. We have lost everything.”

Hours before the ceasefire was signed, aid officials said the humanitarian crisis in Gaza was “as bad as its ever been”. UN-run bakeries run in southern Gaza have not functioned for weeks because of a lack of fuel and flour, depriving the poor of a main source of food.

“If there wasn’t a ceasefire, then we would be screaming,” said one UN official. “We are massively concerned about the law and order and governance situation, and then there is all this trauma and fear that people have kept bottled up. It will all start coming out now.”

Pedestrians and drivers in central Gaza moved around freely on Monday on the main coastal road along the Mediterranean Sea, which is lined by rows of hundreds displaced families’ tents. Israeli troops turned anyone trying to head to northern Gaza back.

A UN report last year said rebuilding Gaza’s shattered homes could take many decades. Merely clearing the rubble will demand huge resources, with unexploded ordnance and asbestos in the ruins slowing the process further.

Even those whose homes are still standing are without water, power and other basic necessities.

Noha Abed, 28, had returned with her husband and three children to the family’s home in the southern city of Rafah, which now has only one liveable room. “Our house was beautiful, a one-storey building with three rooms. We lost everything,” she said.

But after cleaning it and putting their belongings in what is left of the house, she said the family “want to live in it until the rebuilding happens”.

For now, her focus is on securing “food, water, electricity, beddings and blankets” for the family, who had been sleeping in a tent further north for about 10 months, she said.

Despite the difficult conditions, she said that this was “the first night I sleep without being afraid for my children”.