Penzeys Spices
www.penzeys.com
     We cannot say enough about Penzeys as a source for herbs and spices of all kinds. Considering the freshness and variety, you might expect these to be expensive. They're not. You can buy small samples at a nominal price.    See our discussion of herbs and spices in Seasonings. 
They have arrowroot starch, arguably the best thickener for sauces, that is hard to find elsewhere.