I came up with this cute little carrier last year. I put my bottled water in it, place it over my shoulder, and keep my hands free to shop. It's a good use of scrap yarn plus a small exercise in lace knitting in the round. I made mine with a ball of leftover Brooks Farm Yarn Four Play (wool/silk blend).
Lacy Leaf Water Bottle Carrier
Size 7 double points
Worsted weight yarn (about 60 yards - less than 1 oz)
9 oz plastic bottled water (about 8" around)
Pattern will be made available soon on Ravelry.