The bulk herb section of the HEB in Hewitt, TX
Below is some cumin I purchased--two small scoops. Notice the price, 69 cents! The bag doesn't look big, but it filled up the whole spice jar shown in the next picture down.
And yes, that jar was EMPTY. So $0.69 filled up a whole jar which usually costs around $6. Now, that jar was organic*, and so might have been a little pricier than most. But even compared to of the LOWEST priced jar I could find of bottled cumin ($1.99 for 1.7 oz of HEB generic cumin), my bag of cumin was 1/3 the cost! Guess you pay a lot for that jar!
And yes, I've tried similar comparisons with other spices. Even at a pricier store like Whole Foods, the bulk spices were much less than the regular spices at other grocery stores.
Herbs that aren't ground give you an even better savings, usually (since they take up more space but are very light). Bulky herbs, like bay leaves or cinnamon sticks tend to cost A LOT less loose than in jars (typically a savings of 75% or more).
*(SIDE NOTE: If you are concerned about GMO, you should know that very few herbs have ever been genetically modified, probably because they tend to be naturally critter resistant. The only ones I'm aware of are sugar cane, alfalfa, chicory, flax, eucalyptus, rose and chrysanthemum [edible flowers], and tobacco if you count that (and except for sugar, you would not find any of those on most spice aisles anyways). Of course these lists change so you can always check the GMO crops list on wikipedia or this list at the International Service for the Aquisition of Bio-Tech Applications.)