Thanks to Google, a two minute research have made me aware that a mere $4.00 investment at a local Thai market would give me gallons of this sweet goodness.
Oliang powder is a blend of soy beans, corn, and coffee bean.
It runs about $3.00 at any Asian market for about a pound, and you also need a strainer, which I bought for 99 cents at the same place.
You need about 2 TBSP of this Oliang powder per one serving (10 to 12 oz.) so you will be able to make A LOT of ice coffee with just one bag.
Here is how you make this concoction: