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S'well Stainless Steel Water Bottle ($29)

"I always have one full any time I leave the house," Gross says of S'well's BPA-free water bottles. "I just cannot bring myself to buy bottled water anymore. I love that this is indestructible, keeps my water cold, and contains no plastic."

This 17-ounce bottle has triple-layered insulation that keeps beverages cold for 36 hours and hot for 18. Another perk? The opening at the top is wide enough for most ice cubes and the bottom fits into the majority of car cupholders.