Vanessa Ortiz, Luis Torres and Marisol Malave were all ordered held on $2 million bond after their arraignments Friday.
Police say Ortiz and Torres wore masks when they entered the store Monday and demanded that 26-year-old Narote Arun Kamur open the cash register.
Police say when Kamur didn't move fast enough, Ortiz shot him in the head. Police say the pair then fled to Malave's car.
A witnesses told police that the three boasted about what they'd done, with Ortiz and Torres arguing about who should get credit for the killing.
Police say the three lived together in Bridgeport.
It was Bridgeport's 13th homicide this year, after having 12 homicides all of last year.