I just use this.
http://steepster.com/teas/david-rio/133 ... a-thai-tea
I do not use the recommended amount which is 1.5 tablespoons of their tea or tea powder in 1/3rd cup of hot water. Instead I use 1-1.5 teaspoons of tea/tea powder and put it in to 8oz of hot water which I add half and half, or milk to, and put over ice.
I bought it at a department store on sale, and an entire tin has lasted me for more than a year.