Sara.

Option #1
They sell Tazo Chai liquid mix in a box at most Starbucks retail locations. This is a less concentrated version of the exact same mix they use to prepare beverages for customers (as liquids are expensive to ship). However, if you use equal parts mix to dairy of your choice or milk substitute, it is almost the same. By making them yourself, you can control the sweetness and intensity of the tea.

Option #2
This is a little more time consuming, but produces a very flavorful and customized beverage. You can purchase Tazo chai tea bags (either caffeinated or decaf) that have the tea and spices included. Brew double strength (less water)
2 bags for 12 oz beverage (use 6 oz to brew)
3 bags for 16 oz beverage (use 8 oz to brew)
4 bags for 20 oz beverage (use 10 oz to brew)
brew tea for 5 minutes
add warm milk product of choice (equal to amount of water)
add honey and sugar to taste
additional ground spices can be added for intensity
such as cinnamon, nutmeg, ginger, allspice, cardamom, vanilla, etc.
use all of these sparingly if you decide to experiment with spices.

Option #3
Find a recipe for making REAL chai from scratch which has no tea in it at all, and is a process of using whole spices simmered and reduced in half and half. Very rich, a real treat.