The family to which the girl was "sold" had forced her to marry their 25-year-old son on May 1.
Police said the matter came to light after the girl's family members learnt that their daughter had bee sold for R80,000 and that they were kept in dark about the deal.
A case was registered at the Ashok Vihar police station after the victim's mother lodged a complaint.
The arrested people have been identified as Dharamvir, the girl's 'husband', Bharat Kishor Pandey, a local priest, Chandrakala, Chandrawati, Vishnu Nath, Ajay Yadav, Satbir and Tejpal. Police are now trying to find out if some more girls were sold in a similar manner by the accused.
The girl's family lives in Wazirpur area near Ashok Vihar and her parents are labourers, a police officer said. In her complaint, the girl's mother told the police that a few days ago, one of her neighbours told her about a potential match for her girl.
"The girl's parents agreed for the marriage and it was solemnised at a local temple by Pandey. Three days after the marriage, the complainant learnt that the marriage was
in fact a deal. She also learnt that R80,000 was paid for it," said the police officer, adding that they were interrogation the accused to bust a possible racket.