Officers said the incident that took place at a newsagents in Newmarket at around 8.30pm yesterday (Thursday).
A police spokesman said: “A man entered the shop and asked to buy cigarette papers. When the shop assistant opened the till, the offender reached over and snatched cash from inside, before leaving the shop.”
A CCTV picture has been released of a man police believe may be able to help with their investigation in relation to the till snatch.
Anyone with information about the incident is asked to contact PC David Dicken on 101, quoting incident 452 of October 13.