Grocery IQ is a free grocery list application for Iphone and Ipod Touch (and I think some other smartphones). I've got the version for the iPod tOuch.
The initial screen has selections across the bottom for list, favorites, stores, coupons and more. More is basically a preferences screen for initial setup.
Favorites is where you can build a master list of the groceries you typically buy. You can assign items to a particular store, or to 'any store'. You can search for an item, input it by barcode number, use a camera if the ipod has one to scan the barcode, or merely enter an item. When you search, the app will try to guess what you are looking for, so you do not have to type the entire item name.
Unfortunately for many items, there is no generic choice, just a choice between different brands. Searching for "basmati" brings up more than 50 specific brand name items with basmati rice, but not 'basmati rice' itself--you will have to type the whole thing, and assign it an aisle. This is probably the most annoying part of the app.
The 'list' section shows a list of just the selected items. You can again choose 'any store' or a specific store. If you want a particular item once, but do not want to add it to favorites, you can add it to either the 'all stores' or a specific store list here.
The 'stores' section lets you reorganize the order of aisles to match the specific store (with a different order in a different store), and select whether that store will display 'all stores' items.
The app is sponsored by coupons.com. If you are on a Windows system, you can get printable coupons related to your list--unfortunately you will have to install an application that will prevent you from making multiple copies. Although Wife's system can boot to Windows, we don't do it enough to be worthwhile. I am also not particularly keen to install software from an advertising company.
A relatively simple app, but does the job well. Even without the coupons, it is worthwhile.