How about a fit for purpose Grocery Comparison site?

Comparison sites are very much in the news, at the moment it's with reference to energy switching but they're significant around insurance and other services.

A hight-street grocers

Well yesterday we went to Sainsbury's to pick a couple of things and as is generally the case we bought quite a bit more than we'd anticipated - not a problem it's stuff we'll eat/use.

I don't think shopping is only about price but for some people the overall cost is very significant.

While we were out  and as we returned I wondered if there's a website that helps with shopping in your locality - many people (often the old and/or poor) are time rich but money poor how can they get the best deal on groceries - do Aldi or Lidl have what I want at a better price?.

Have had a quick look at what the web has seems that what's there at the moment (like supermarket.co.uk for example) doesn't do the best job it could - what I'd envisage is something simple, where you can compile a shopping list from your products (pull downs or scan the codes on the product in) and then say where you are (postcode or similar)  and how far you're willing to walk (say one mile) and the number of shops (say 4) you'd be willing to visit.

Or are they cheaper for my milk?

I would reckon an SQL type enquiry of grocery sites (tesco.com etc.) would make the data available - has anyone seen something that does this job or could run with the idea?