Frozen Vegetables - Make your own frozen vegetable combinations by buying bags of individual vegetables and combining your favorites. Re-package in resealable plastic bags and freeze. Try adding chopped onions, garlic or cooked pasta to the vegetable mixture as well.
I want to add to this - you can divide your veggies, fresh or frozen, into more 'needable' sizes. I often buy a large package of frozen vegetables but won't be needing the whole package at any one meal. You can divide them into smaller packages so that when needed you can thaw only what you need. I often buy vegetables such as celery, bell peppers and onions but find that they won't be used before I find they have to be thrown out. I'll chop these up, scatter in a single layer on a cookie sheet with sides, freeze and then place into a bag for later use. These work perfectly in soups and stews.