I used to pack a bottle of mineral water into my school bag everyday. That way, I can ensure my body gets its minimum requirement of H2O. My favorite brand back then was Ice Mountain, Singapore's leading brand. $0.80 per 500ml bottle or $0.30 if you order by the carton.
As I got older and started working in enclosed areas, I find myself popping vitamin C tablets into my water bottle to keep healthy and bug-free. So I almost couldn't believe it when 50 cent the rapper announced his line of Vitamin Water - vitamin enriched fruit flavored water. In my opinion, all office workers need to order cases of this and stock up so they can have at least 1 bottle a day. Slightly more expensive at $1.70 a bottle, almost the same price as Evian. Shopping around the internet, I got my case of Ignite for $1.20 a bottle and the guarana extract keeps me cool during these hot summer days.
* prices from NTUC Fair Price, my carton of vitaminwater came from Qoo10.