Two parents from Zamfara's Wadzamai village said they paid 20,000 naira ($43.50) each and their children were among those released on Friday and had suffered from severe malnutrition.
A village head in Wadzamai said 11 people were still being held but two were killed trying to escape from their captors.
A police spokesperson for Zamfara said they could not immediately comment.
Kidnappers in Nigeria often keep their victims for months in the forest if a ransom is not paid and also demand villagers pay protection fees to be allowed to farm and harvest their crops.
Gangs of armed men have attacked hundreds of local communities across northwestern Nigeria in recent years, while Islamist militants continue to stage attacks in the northeast.
