tsp spices is one of the cooler ideas I have come across recently. Think of it this way: imagine having in your food bag sealed mini bags of spices and herbs, all organic, and ready for you to use in your trail meals.
you can easily carry a wide range of items with you. They are water tight and stay fresh till you need them. (Cinnamon in oatmeal is always a good choice!)
As for buying them, they sell online as well in stores, such as Sur la Table. They have a store locater section here.