I used to buy my chai mix for brewing at home in Santa Cruz, Calif because that was the only place I knew of that sold it If there's anyone else in the Santa Barbara area in the same position as I was, just to let you know, a store called "The SuperNatural" has a large selection of dried herbs and spices, including three pre-mixed types of chai-type spice teas. One was called "chai," another was called "Yogi Blend" and I forget the third.
They're all slightly different, one has more clove and citrus, another has more cinnamon, etc. All taste good, especially when you use your espresso machine to froth the milk! Also, Trader Joe's sells a 'ready-to-drink' chai tea that I find tasty as well. They're sold in those UHT-type cartons that have a shelf life of a year (as long as you don't open them! otherwise they last a week in the fridge) So I keep a stash in my pantry, just in case I need an instant chai fix in the middle of the night.
I hope someone finds this information helpful!