A male member of staff was threatened with a knife and tied up at the Co-operative on Skirkbeck Road in Boston, before the thief made off with the cash.
A twenty-two year was arrested in connection with a robbery at the Co-operative on Skirkbeck Road in Boston. He has since been eliminated from the enquiry.
Police are appealing for any witnesses who were in the vicinity early on Saturday morning and who may have witnessed the offender approaching or leaving the store.
Anyone with information should contact the police.