this is my favorite place.... (added some prices)

Monterey Bay Spice Company

 www.herbco.com/c-2-bulk-herbs-spices.aspx

There are so many places to choose from. I liked this one because the product smells so fresh, they seem knowledgeable, most of it's double wrapped in plastic and mylar and it gets to me very fast (2-3 days, but I live sorta close).  They don't have everything though, and I've used other places that aren't as good for things they don't have.

Just checked out the price of yucca root and it's $22 at starwest and only $9 at monterey bay, and ashwaganda is only $3.50 at MBS and $13.92 at SW. And check out turmeric, it's only $2.50 a pound or $9.50 for organic at MBS.

There's a ton more to choose from at SW though. 

Let us know how your stores turn out.