A £500 reward is being offered by police hunting a petrol station raider.
The man, who was armed with a knife, got away with money from the till at the Mike Thompson service station on Newport Road in Stafford on Saturday.
Detectives say the offender entered the shop at about 2000 BST and asked to buy some cigarettes.
When the male assistant opened the till he threatened him with the knife and reached across the counter to snatch some money.
Knife wounds
The assistant suffered minor knife wounds to his hands during the incident.
This is the fifth time the shop has been a target for crime in the past month, including incidents of vandalism and shoplifting.
The man is described as around 5ft 10in tall, slim build with short dark hair and designer stubble.
He was wearing a light grey jacket and dark trousers and police believe he was in the shop an hour before the robbery.