In honor of simple, yet powerful messages, I have (with the help of HZ and BB) created a bumper sticker version of the bottom line on this blog: "Some Water for Free... Pay for More" [click to see the full-size version]
You can order bumper stickers singly ($4/each), or in packs of ten ($3/each) or 50 ($2/each) at CafePress. (I may also send some to loyal aguanauts...)
Feel free to use the (intact) image elsewhere.
After assessing the success of this sticker, I will consider other slogans :)