I have been buying spice mixes and hard-to-find ingredients like pomegranate molasses online from Herbie's Spices for years. They sell products in small quantities so they keep fresh, which is perfect for the domestic cook.

If you doubt whether it's worthwhile paying more for something like za'atar, a Middle Eastern blend, just compare the ingredient list at Herbie's website, with that of a well-known commercial product.

Herbie's website is easy to use, and they ship promptly.