Buying frozen vegetables can often be cheaper than fresh. And they often taste fresher than the tinned. They can be thawed under running cold water and used as fresh.
Meat and fish are often found frozen. Though we buy frozen fish in large packs, I have yet to find a way to cook them so that they taste like fresh. But I still enjoy them. When we buy fresh fish and meat and do not think that we will use them in the next day or two, we will freeze them. This makes them last much longer.
Though many are in the habit of shopping on a frequent basis to get fresh foods, we have found that we do not have enough time on our hands to do this. We usually shop once a week for everything we need that week. We have learned to use our freezer to keep things still fresh at the end of the week.