Large amounts can be purchased when they are on sale, then used when they are not. This may also require you to change your eating habits just a bit - like eating more whole grain and legume foods that are inexpensive but nutritious. But whatever you choose to store, be sure it's something you can eat or it will never get rotated. Whatever you store, insure it is as nutritious as possible with the 50 essential elements required for good health . But if you do this, be sure you have a cool, dry place to keep it.
Bugs are always a serious concern.
If you haven't bug proofed your food you need to check it every few weeks to insure it stays insect free. Can your garden produce in bottles. This works best for fresh vegetables and fruits, and even meat if it is done correctly. However, know that after two years, wet packed foods in cans or bottles lose much of their nutritional value. Dehydrate your own foods.