Retailers can edit their offers as they compete to make the sale.
Walshe, 40, said offers will not be just about the price of the item - retailers can also offer 'deal sweeteners' such as extended warranties or free delivery,.
"The deals get better for the buyer as the auction progresses."
Pricemaker is free for consumers to use and currently has televisions, kitchen and laundry whiteware categories to choose from.
Depending on how things go, the plan is to get more product categories launched as soon as possible, Walsh said.
Retailers will be charged a flat fee per month per category, rather than a fee on each transaction.
A limited launch is underway in Auckland and Wellington, with three major retailers signed up so far - 100% Appliances, Magness Benrow, and a third which could not yet be named.
Two others big-name players are "sitting on the sidelines", Walsh said.
"We've had some really big retailers say 'you show us that consumers want this and we'll join as well'."
Walshe, who is from Wellington, said he first came up with the idea in 2008 but ramped things up after being made redundant in March this year.
He and a business partner have invested about 25 per cent of the capital, with the remaining start-up funds coming from "a friends and family capital-raising round".
"Being in banking, we work with guys who have a little bit of money, so we tapped into that," Walsh said.
He said it was not a completely new concept but the idea had become much more viable in recent years.
"Smartphones are now in every second pocket and online shopping is more commonplace."
Walshe worked at Westpac from 2006 to 2010, then with ANZ as a senior FX trader until March this year.
