Police said the man was trained how to use the cash register at the Mesa store on April 27 after falsely claiming he was a new employee.
The suspect returned to the store twice that day to make purchases. On the final visit, the clerk commented on his photo ID when the suspect was trying to buy beer, and the man allegedly pulled a gun and forced the woman into a bathroom.
Police said the suspect pretended to be the store clerk and was helping customers when the real clerk broke free and emerged with a gun. The man fled with stolen money, police said.
Marc Antoine Stovall, 21, was arrested Monday in Phoenix and was booked for investigation of armed robbery, kidnapping and third-degree burglary. He admitted to the crime during an interview with investigators and was in jail Tuesday, Mesa police spokesman Christopher Arvayo said.
It was not known whether he had been assigned an attorney.
