[case thrower]

I use 1.5L Diet Pepsi bottles in my old water bath cooler.  Has to be the Diet, though.  Regular Pepsi bottles won't work.  When I get my fermentation chamber built, hopefully in the near future, I will use 1 gallon Lipton Tea jugs.  They're much thicker so they shouldn't split like the milk jugs.

Sweet or unsweet tea jugs?   

Diet Citrus Green Tea seems to work the best.  And they have to have a green cap!

[euge]

Arctic Ice

Looks promising for what you want.

There's all sorts of freezer packs or ice packs available out there. They are fairly cheap. I used them for years to keep my fermenters cool. Then I moved to freezers, which perform better and are a lot less work...