The cheapest guy I know...

... is me.

In my attempts to drink less soda, I've been substituting barley tea (麦茶, 보리차). The vending machines at work sells 600 mL bottles for 130 yen, or about $1.25. [left]
I thought that was a pretty good deal until I saw the same bottles in the nearby govery store for 85 yen. [right]

And that, I thought, was a good deal until I saw the 2L bottles for 138 yen. I bought a few of those and filled up my 600mL bottle to take to work. [left]
But then I saw found the best deal. For 158 yen, you can buy 52 tea bags and make your own [rihgt]. So now what I do is measure out two liters of water and bring it to a near boil, then turn off the burner and throw in a barley tea bag. After it cools down overnight, I put it in the 2L bottle, and then fill up my 600mL bottle from that.

So now, I can get 2L of 麦茶 for about 3 cents. That's three days worth of barley tea, with each 600mL bottle costing about a single penny each.

If cheap were a challenge, I'd do pretty well.