Plastic storage containers
I use some red & white plastic storage containers I picked up at either Home Depot or Lowes (can't remember...). They stack when not in use, are pretty durable, cheap ($~ 5/ each), and tile the back of the SUV when on a road trip. I always have one in the back loaded with my "Car stuff". On a road trip, I load up one with dry food, and another with cooking/ camping supplies, etc, and anything else I need. They tile really well into the back of the vehicle, and you can actually lay in a complete layer of these if needed, and then put things like duffel bags, and etc on top -- or tile in another layer if needed. They're semi-transparent, so its easy to see what's inside.