Alisios, you've been robbed.
For the first time since your above post, I've been to a local (East) Indian grocery for spices. (I'm fortunate to have two to choose from; if any other East Bay'ers are reading this, check out Milan Market at 9th & University in Berkeley.)
Here are today's prices on the three spices I purchased:
(Yellow) mustard seed--$2.99/lb if purchasing ≥ 1 lb; $3.49/lb otherwise.
Celery seed--$2.49/lb if purchasing ≥ 1 lb; $2.99/lb otherwise.
Powdered cinnamon--$5.99/lb if purchasing ≥ 1 lb; $6.99 otherwise. So I ended up with 13 oz. (scooped 'em into a very small brown paper bag) and paid $3.80 for this truly princely amount of cinnamon. Some will go to ant control; some will stay in the kitchen.
**NOT** expensive when purchased this way; I hope you have an Indian grocery near you!