Although soft drinks are incredible cheap in Thailand, they are also not really healthy and I avoid them wherever I can (although I do have a thing for Pepsi Max, I have to admit). But is actually even cheaper to make your own refreshing soft drink. My favourites are butterfly pea (Cha Am) tea and Pandan leaf (Bai Tuei) tea.
You can buy both at many OTOP sections in supermarkets or at local markets. Pandan is also easy to grow in your garden, and butterfly pea makes a nice colourful hedge on your fence. For me it is more convenient to buy the dried leaves.
For a litre of tea you need about 3-4 table spoons of leaves. Just pour hot water over it (you can use a tea strainer) and let it infuse for 5-8 minutes. You can also mix the leaves to have a even better tasting tea. Use some sugar or sweetener, add lime juice (it will change the color of the butterfly tea to red) and cool it.
The perfect drink for the climate in Asia.