The ambassador's convoy was moving at high speed when the seven-year-old was fatally hit in April.
The US provided the family with 1m Central African francs (Â£1,257).
The boy's family also received two cows, flour, onions, rice, salt, sugar, soap and oil, according to the Associated Press news agency.
The US said it would also build a well to provide fresh drinking water for the boy's community, located near the northern city of Mokolo, according to state department officials.
Department spokesman Jeffrey Loree described the contribution as a "compensation package commensurate with local custom, as well as the needs of the family and village".
"US diplomats have visited the family on several occasions following the accident and will continue to provide all support possible," he added.
Ms Power was on a week-long trip to show US support in the battle against militant Islamist group Boko Haram when the accident occurred.
The boy, Birwe Toussem, was among villagers lined up along a two-way highway to greet the ambassador.
He ran onto the street as the motorcade drove by at about 60mph (100km/h).
An armoured jeep struck the boy, initially stopping, before US security ordered it to continue travelling through the unsecured area, the AP reports.
An ambulance in the caravan immediately responded to the scene, but the boy died shortly thereafter.
Cameroon's government, local aid organisations and the UN also donated 5m francs to the family, bringing the pay-out to more than $10,000 (Â£7,393).
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The US has compensated the family of a Cameroon boy who was struck and killed by a vehicle in UN Ambassador Samantha Power's motorcade.