Bags of nuts, especially Walmarts Cinnamon Toasted Almonds, and Target's cinnamon toasted pecans work well for me. Filling and relatively health. Vacumn sealed cans should work well too.
Our local Good Will store frequently has stainless steel water bottles (Kleen Kanteen or Yeti type) for sale for $1-2. A drop of bleach added to the water should keep it algae free indefinitely.
BPA free hard plastic water bottles (Nalgene and others) may just be advertising hype. Apparently BPA has been replaced by BPS, thought to be just as hazardous. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwjnmsCfnNnPAhXIFT4KHdW7BawQFgglMAI&url=https%3A%2F%2Fwww.scientificamerican.com%2Farticle%2Fbpa-free-plastic-containers-may-be-just-as-hazardous%2F&usg=AFQjCNEhwexhk2ioxfqdDA4iSF0YYPqYjQ&bvm=bv.135475266,d.dmo
I stick with the stainless steel water bottles for that reason.