In Rio, coconuts abound. Go to any drink stand along the beach and you'll see a sign for "Coco" above a pile of green coconuts. I've also seen them sold at street-side farmer's markets, and at New Natural, the organic salad bar I go to for lunch.
You can buy a single coconut and drink its water directly from the shell, or you can buy by the bottle. Each day, they fill up half-liter and full-liter bottles by hacking open one coconut at a time with a machete. It's amazing to watch.
Lately, I've been drinking a bottle for a mid-afternoon pick-me-up. It's same-day fresh, it's delicious, and it's cheap. One liter cost 10 BRL, which is $2.50 US.