Abdul-Munim Omrani, 33, persuaded a charity to give him a peddler’s cart. He now uses it to sell hot drinks near a beach at a cheaper price than the seaside cafes skirting the shore.

He can make around $12 a day, he said, but he was chased away by the municipal police. His rust-streaked cart, with a deflated wheel, was parked near his peeling pastel-painted home. “I felt defeated,” he said. “That man took away my livelihood.”

On a recent day at the Gaza port, men pushed children in toy cars decked with flowers and glitter, charging 50 cents a ride.

Boys work, too, making up for absent, sick or dead fathers. Mohammad al-Ahl, 13, sells polka-dot balloons for 25 cents each, cheaper than the Bugs Bunny-shaped balloons that older men typically offer for a dollar. On this day, business was quiet. He sat silently by the port’s cheery blue, pink and green wall.

Israel places severe restrictions on the import of building materials, saying they have been used to build tunnels to conduct attacks on Israel. The Egyptian government, a bitter enemy of its homegrown Islamist party, the Muslim Brotherhood, has taken extraordinary steps to shut down the tunnels that were the lifeblood of the Gaza economy.

Egypt has opened its border only five times this year, part of a broader policy to punish Hamas, which aligned itself with the Brotherhood, Egypt’s former ruling party, a decision that backfired when the military seized power in mid-2013. The tunnels were Hamas’s chief source of revenue. It was their closing that set off the new import fees in May.