The incident took place yesterday afternoon when the victim, identified as Sunil Kumar, had gone to buy soft drink with his friend at BTR Corridor near Chirag Dilli.
"The duo had four glasses of drink, each costing Rs 5. However, Sunil allegedly refused to pay the vendor for the drink. A heated argument ensued and the vendor, identified as Deepak, whipped out a knife and stabbed Sunil in his abdomen and fled the scene," said a police official.
"Deepak (40) was arrested from his house at Khirki Extension. We have also recovered the knife used in the commission of the crime. A case of murder has been registered," he added.
Sunil lived with his parents in Panchsheel and was pursuing BA from correspondence, police said.