The store on Shrewsbury Road filled up quickly when it opened with people travelling from a wide area.
Cutting the ribbon on the store was regular customer and long time shareholder, Mr Peter Clare from Hengoed, who is also a Selattyn and Gobowen Parish Councillor.
He bought shares in the company when it went public in 1957 and has been calling for a larger store for Oswestry for many years.
"It is a shot in the arm for this area, not just the town but the villages and further afield," he said.
He and his wife, Isobel, praised the company for providing a community room, next to the cafe, that local groups can use, free of charge.
Oswestry mayor, Councillor John Price, said he was pleased that the development had brought with it 95 new jobs in addition to the 75 existing ones.
And he said that he hoped it would bring more people to Oswestry from surrounding towns and countryside.
"I hope they will come here, do some shopping and then come into Oswestry Town Centre and do more shopping and use the services."
Shopper, Lee Lewis, said he liked the Market Street area where staff can be seen baking bread and preparing meat and fish.
"The staff have been so friendly and helpful, it is a fantastic place," he said.
Sandra Lewis said she was pleased to see a cafe in the building.
"I think that will bring people in to shop and enjoy something to eat."
A recent, meet the producer event, led to the current stock of local food on offer at the store with information banners explaining about the companies.
Community champions in the store say they will continue their work to help charities and good causes. This year £15,758 has been raised to help local good causes and £1,319 for the company's national appeals.