The incident took place late last night when the victim, Manohar Gamne (54), went to buy eggs at a neighbourhood shop in Rambaugh, said Thane police PRO Sukhada Narkar.
Gamne allegedly paid Re 1 less to the shopkeeper which led to an argument between the two. The shopkeeper abused the victim, Narkar said.
The victim and his son later went to the shopkeeper to ask him why he hurled abuses. This led to another round of verbal exchanges during which the shopkeeper's son repeatedly kicked and punched Gamne, leading to his instant death, the official said.