I'm an italian developer. One year ago I created an application for the shopping list. Initially I only developed it for me, but one month ago I deployed it to the marketplace.
I've created both italian and english version. the italian version is going very good with already 9 very positive reviews in one month.
This application is simple to use, I used the metro guidelines so that it's easy to use.
There is also a feature that no other application has: the category order of a store, so that when you add items to your shopping list, everything is ordered in the right order of the store you have configured (you can configure more than one store).
I've created two version:
one free with advertising Easy Shopping Free | Windows Phone Apps+Games Store (United States)
and another at 0,99$ without adverstising: Easy Shopping | Windows Phone Apps+Games Store (United States)
I hope to have already a good english database, but I would be glad if some can help me to add more new products.