That first grocery shopping trip after you move - it's painful, and expensive. There's so much to replace! While they don't really go "bad," ground spices lose their potency after 2-3 years, and dried herbs after just 1-2 years. Since we move every 2-3 years, I figure moving is a good guideline for switching out those herbs and spices.
Thankfully, you have a couple of options for getting your spices at significantly lower prices than you'll find in the regular spice aisle at the Commissary or grocery store. The easiest solution is to find the aisle with the international or Mexican foods. Military commissaries carry the Badia brand, and typically stock it with the Mexican products. (I haven't figured out why. It is an American company, founded by a Cuban exile.)
Badia spices, or other spices found in the international sections of grocery stores, can be 50% less than their more recognizable brand-name counterparts. The bottles aren't as fancy, but the quality is fine. Smaller Commissaries may not carry the whole line, but most have at least a small selection of the basics.
If you're looking for something more unusual, or your Commissary has a limited selection, you might want to investigate some other sources. Many decent-sized towns have a variety of specialty shops selling foods from different regions, and prices can be incredible. Some health food stores sell spices and herbs. And, you can always order from one of the many online spice purveyors. I haven't done it, as it feels a little weird, but there distinct advantages, including amazing prices (oregano for $6.00 a pound???) and the ability to order smaller or larger quantities.
Once you've bought your bargain goodies, help them last by storing them in cool, dry, dark locations (not on the wall above the stove) and don't shake the bottle directly over your steaming pots.
Spices can make even the most simple foods shine, but they shouldn't break the bank to do it. Stay away from the spice aisle and explore some more affordable ways to add more flavor to your foods.