So, I don't ever drink enough water, but I need to work on that. Anyone have a suggestion for a good, light, durable, leak-proof water bottle? I need something that can be stored upside down without leaking if I forget about it and it rolls around in my car. I also need something fairly cheap since I expect to lose it at least once (I've never carried one), and light. Also, I need it to fit in a cup holder. Thanks.