I was going to mention the WaterBob. Those have been selling on Ebay for $25 for at least the past year or so, it looks like someone copied the idea. I've read some preliminary reviews on other sites, and it seems to work well, and i think it even comes with a siphon to get the water out.
WARNING & DISCLAIMER:
SELECT AND USE OUTDOORS AND SURVIVAL EQUIPMENT, SUPPLIES AND TECHNIQUES AT YOUR OWN RISK. Information posted
on this forum is not reviewed for accuracy and may not be reliable, use at your own risk. Please
review the full WARNING & DISCLAIMER about information on this
site.