the 20 oz bottle is made from the safe kind of plastic & has a built in filter that only costs about $3 to replace every 2-3 months.
you don't even have to do the math - they do it for you:
"The Fit & Fresh LivPURE™ Filtered Water Bottle can save the average bottled water drinker more than $500 per year (using an average price of $1 per bottle). LivPURE™ filters have been certified to be effective to 75 gallons, an amount equal to 500 bottles of water."
so instead of worrying about the taste of different tap waters or filling your bottle with water cooler water - you can purify on-the-go with this bottle that will only cost you about 10 days worth of bottled water. and in case that doesn't sell you on LivPURE - think of all those empty bottles that you won't send off to the landfill.