This week Sunny Bal opened the doors to his new family-run shop, Thames Discounter and Takeaways.
Mr Bal, who has run convenience and discount stores for more than 20 years, said he had no doubt he would be able to pay his staff and make enough money for his family without charging the high prices supermarkets do.
The industry markups were so large that all players, including the duopoly of Foodstuffs and Woolworths, would be able to lower them and still make money, he said.
His plan was to attract customers with cheap prices and earn a reputation, which would allow him to "make a reasonable amount of money and make a good living".
But that was not how the supermarket giants saw it and instead put strain on the cost of living for the profit of a few, he said.
"They’re making millions and billions and millions.
"We are against it."
The community was "not stupid" and did not want to shop somewhere like that.
He had brought the price of essentials down so people could afford them, such as selling bread for as low as $1.29 and two litres of milk for $2.69.
The bread was a loss leader, but helped to get people in the door and build a reputation.
What he could discount and by how much was heavily impacted by the duopoly, as they had a lot of control over the wholesale market, he said.
"It’s only two players in the market. It should be more.
"They do control the prices and they do control the suppliers as well, directly and indirectly.
"We have to keep an eye open when the deal comes and get it in bulk."
He also planned to stay competitive on a national level instead of just local by comparing his prices to supermarkets outside Oamaru, such as Pak’nSave.
He had run successful discounter businesses throughout the South Island, including Nelson, Balclutha, Ashburton and Christchurch.
There were plans to open a new one in Dunedin as well.
In 2016 Mr Bal and his wife Tania made headlines in 2016 after his Invercargill store became so popular parking became an issue.
Now they would be living in Oamaru with their 2-year-old daughter, he said.
"We are a part of the community, who is middle to lower class.
"The community supports you a lot if you do something for them. They will use their money wisely and bring it back to you."
He believed it would not just act as a convenience store, but people would travel from other suburbs to shop there.
The store will serve hot cabinet food and takeaways will be available by next month, which Mr Bal believed would appeal strongly to tradies.