A court heard the victim "turned to jelly" when Christopher Mosby climbed on the counter at the Betfred business on Horbury Road, Lupset, Wakefield, and waved the imitation weapon in her face.
Leeds Crown Court was told Mosby targeted the store at 9.25pm on March 14 this year shortly before closing when the woman was alone.
Richard Holland, prosecuting, said the victim pressed the panic button under the counter but it failed to work.
She was ordered to put banknotes and coins from the till into a bag as Mosby swore and made threats.
Mosby fled with Â£175 but was arrested after a police officer recognised him from CCTV images of the raid.
Mosby also hit a man over the head with a pool cue during a disturbance at the Magnet pub, Dewsbury Road, on December 8, 2016.
The court was shown CCTV footage of Mosby picking up a cue from the table and making threats with it during a confrontation involving a group of men.
The disturbance continued outside, where Mosby snapped the cue in half over his knee before using part of it to hit a man over the head.
The victim needed hospital treatment for a gash to the head.
Mosby was also caught on camera at a shop on Westgate, Wakefield, selling a games console which had been stolen hours earlier during a burglary at a house on Broadway, Lupset, Wakefield.
Mosby, of Lindsay Avenue, Lupset, pleaded guilty to robbery, unlawful wounding and handling stolen goods. He also asked the court to take a schedule of 11 offences, including five burglaries, into consideration by the court.
Mr Holland read a victim statement to the court on behalf of the robbery victim.
She described how she had suffered from depression and anxiety as a result of her ordeal.
She said: "It terrified me to a point I have never been before, all for the small gain of Â£175.
"I find it hard to engage in conversation with colleagues or customers. I feel nervous every time the shop door opens.
"I hope the offender has had time to reflect on his actions that night. I don't ever think he thought about me or what a selfish act he did to me."
Sean Smith, mitigating, said the offending took place during a period when his client had become hooked on drugs.
Mr Smith said Mosby had built up debts with drug dealers and threats had been made against him and his family.
Acting Detective Sergeant Steve Wright, of Wakefield CID, said: “Mosby put the staff at the bookmakers through a frightening ordeal, threatening them at gunpoint.
“We hope the significant sentence he has received will provide some source of comfort to the staff and serve as a warning to others of how seriously the courts view offences of this nature.
“Mosby now has seven years in total in prison to consider his actions.”