It happened around 4 p.m. Monday on the 2200 block of North Broad Street.
Police say the 38-year-old customer was shot four times during the altercation with the suspect.
The victim was rushed to an area hospital where he later died.
No arrests have been made.
No other injuries were reported.
Anyone with any information is asked to call police at 215-686-TIPS.
At least 12 people were shot in Philadelphia from Monday afternoon to night.