Labour MP John Denham has called for supermarkets to publish detailed information on prices to help shoppers get the best bargains.
Mr Denham said consumers should be able to use smartphone apps to spot price variations between larger supermarkets and their smaller branches.
This would "drive sharp practice and misleading pricing out of the marketplace", he said.
Mr Denham, a former Cabinet minister, was speaking as he introduced his Supermarket Pricing Information Bill in the Commons on 15 January 2013.
The bill would require supermarkets to publish detailed pricing data on all the goods they sell in a standardised, accessible, online format.
Mr Denham told MPs: "None of the information I want shoppers to have is secret, it's all publicly available.
"The problem is to get our hands on it we would need an army of volunteers to go into every store, every day, to check on the prices of products."
Giving the information to shoppers would "even things up, just a bit, between the supermarket giants and the consumer".
He added: "It is hard to be sure when a price promotion is a bargain and when it is a rip-off," he said.
Mr Denham's bill was given an unopposed first reading but it is unlikely to make further progress due to a lack of parliamentary time.