IPSWICH families struggling with the cost of living are expected to be the first to benefit when US warehouse giant Costco opens in Bundamba in November.

The company's massive buying power, unique membership system and savvy business model means shelf prices are significantly lower than in other grocery stores.

The model won't work for everyone however. Families who aren't in need of super-sized food packages and household supplies won't benefit from the bulk-buy system.

The warehouse will also have a petrol station offering 'exclusive' prices to members. The business model has created a 'Costco effect' in other parts of Australia, which forces near-by petrol stations to lower their prices to stay competitive.

Costco Australia managing director Patrick Noone said it had already proven successful in other markets in Australia.

"Competition is always better for pricing. In all the other markets we have opened, we see more competition in petrol pricing," he said.

"Because we are a paid membership business, we always want to offer our members the best prices on fuel.

"I think you'll see an impact in the local market for sure."

Minister for State Development Cameron Dick said the $50m investment was a strong commitment to Ipswich.

"Everyone loves a bargain and that's what this project will deliver. What more could you ask for; lower prices for shoppers and more local jobs," he said.

"We know Costco has a strong connection to Queensland.

"Much of their produce is sourced from our state, particularly their beef and pork. We are delighted they are expanding their retail footprint.

"For shoppers it means lower prices and it means more local jobs."                                                                                                                                                                      

How the Costco model works

Annual membership fees allow the company to keep over-head costs down. A 'no-frills' policy means most of the merchandise is displayed on the original shipping containers. Members can re-coup the cost of their membership through savings in-store.