If you're looking into healthy cooking, definitely make sure you have almond flour in your cupboard. This has the protein of nuts and the texture of grain flour.
In essence, all almond flour is is taking almonds - the oblong nuts you enjoy raw - and grinding them into a powder. The better quality the almond powder is, the more smooth and uniform this flour product is.
Many of the best cakes, cookies and pastry products are made with almond flour. This is more expensive than grain flour, because almonds grow on trees and are harder to grow and harvest than fields of grain are. On the other hand, almonds are far more healthier for you than a field of grain is!
The best way to store almond flour is in your freezer. That way it stays fresh and flavorful for whenever you decide you're going to use it.
I always suggest going to your local health stores to look for almond flour. Any flour product is going to be heavy and you can easily pay more in shipping than the actual product costs. However, some people live in nutritional wastelands where they can get their hands on even the most basic of healthy foods. If that is you, then there are still solutions.
Here are some websites that provide almond flour for you to buy, if you can't find it in your local store.
King Arthur Flour
Bob's Red Mill