+1 on super-cheap tough bottles; I've used smartwater and similar bottles for decades for that. Silicone water bottles are also great if you want an upgrade. In above-freezing conditions, I love to freeze my water bottles the night before heading out so I can have ice water.

Similarly, they make silicone and tough-plastic reusable ziploc-analog bags now if you're trying to reduce fewer-uses plastic in your life.