One way we do this is through a simulated grocery shopping experience.
I created a mini shopping experience on a bookshelf. We have a variety of empty food boxes and containers. My first thought was to make mini departments and have a "refrigerated' section...but I haven't had time to be that awesome yet. :)
I created two levels of shopping lists, one including pictures and the other with only words. Each list has 3-4 items on it. I taped a folder with the directions written on it and each level goes in one of the two pockets.
Another way we practice this is during our work task boxes. This is very similar to the grocery shopping set up, just on a much smaller scale. Student look at a shopping list and fill the bag with those items. I have shopping lists with pictures or with words, ranging from 3 to 5 items. This task is available to download at my TpT store.
I've talked about how much I love the GFCLearnFree website before. Seriously, if you are looking for functional life skills, you will find an interactive tutorial in their Everyday Life section! The grocery list tutorial goes over finding the right aisle and then finding those items on your list. Did I mention its interactive? Awesome! :)
And then there's my grocery store file folders that I've talked about in detail here. There are a total of 10 file folders, 2 which specifically deal with shopping from a list and the other cover a variety of grocery store topics.
And I almost forgot! I created this grocery store community unit that I haven't even been able to use that. We will start using that unit the month of our grocery store trip.
Honestly, I didn't realize I had so many grocery shopping resources when I started to type this post! What other things do you do to prepare your students for grocery shopping? I'd love to hear about them!