For Americans: mason jars come in a plethora of shapes and sizes, and are dirt cheap. :) I use a quart size as my water glass and we bought Cuppow sippy lids in both diameters to make them easier/safer/neater to use in challenging situations (cars, kids).
Cuppow: http://www.amazon.com/s/ref=bl_sr_kitchen?ie=UTF8&field-bran...