A burglar stole £5,000 takings after sneaking in to the staff area of a Gainsborough shop, Lincoln Crown Court was told.
James Wareham was chased from the store by the owner but escaped with the cash.
Phil Howes, prosecuting, said that Wareham entered the Food Store, on Heapham Road in the town, while the shop was open.
Mr Howes said: “It is a small corner shop. There is a staff area with a ‘staff only’ sign.
“The defendant ran into that room. He picked up two handfuls of cash and ran out with the money.
“The owner did try to give chase but his mobility was restricted because he’d had a recent operation and the defendant got away with that cash.”
Wareham, aged 24, of no fixed address, admitted burglary as a result of the incident in February.
He admitted a separate offence of theft of a bottle of vodka from a local shop and also admitted being in breach of a suspended jail sentence imposed in November 2015 for threatening behaviour during an incident at Lincoln County Hospital.
He was jailed for a total of 44 weeks.
Judge Michael Heath, passing sentence, told Wareham: “The only sentences I can justify for these offences are immediate custodial sentences.”
Hannah Walker, defending, said Wareham had already had a troubled upbringing and had a record of previous offences, but was making attempts to sort out his life.
She told the court “He has worked in the past and would like to return to that work.
“He has a girlfriend living in Gainsborough and will be able to live with her in due course. He is in a position to try and rebuild his life.
“He is someone who would benefit from sustained input from the probation service.”
Miss Walker said that the burglary was an opportunistic offence and Wareham apologised to the shop owner for what he did.