The driver who mowed down people with a truck in Manhattan, killing 8, was known as an “erratic” customer who berated the cashiers at his local supermarket.

Sayfullo Saipov, 29, was notorious for his behavior at the Farm Boy Super Fresh Supermarket on Getty avenue in Paterson, NJ, the manager said.

“Every time he came here he was always erratic or arguing with the cashiers,” she told The Post about the terror killer. “He would get angry very fast…. he would break the cans, dumb things.”

The manager, who declined to give her name, said Saipov was very rude to the cashiers, and called them “uneducated.”

“I feel like he was prejudice to the cashiers — whether they were covered or not in a hijab — he would belittle them,” the manager said.

“He was talking good English, proper, but he would call the cashiers dumb, uneducated — how they didn’t know how to scan the items.”

Saipov, who is in police custody and recovering from a gunshot wound, also regularly argued about the price of Canada Dry Ginger Ale.

“Soda was the problem. He would come here and buy soda,” the manager said.

“He would give us a hard time on the 12-pack Canada Dry — if it was one price he would want his own price. It was always the soda, always a problem with the 12-pack of cans. Always a problem.”