They don't really sell in bulk, but SPICE STATION in Silver Lake is the bomb. They certainly have the freshest spices I've found since Le Sanctuaire left town. You can buy in as little as 1 oz., but you could get any quantity you need. They also have hard to find spices. You might never buy a bulk spice again after trying them. They grind to order.
I get common whole spices in larger cel bags from any local Latino market. Inexpensive but only buy what looks new.
Penzeys is good for harder to find product. Cost Plus also has a good selecton of spices.
The only thing I go to Whole Foods for is bulk items like WW flour and the like.
Cost Plus World Market
10860 Santa Monica Blvd, Los Angeles, CA 90025
Smart & Final and Costco both carry a lot of the basics in large containers.
If you'd rather measure them out yourself instead of buying them prepackaged, the Santa Monica Co-op and Rainbow Acres both sell bulk herbs & spices.
Smart & Final
10113 Venice Blvd, Los Angeles, CA 90034