Old Grocery Bags: while this would be the least expensive option, old grocery bags don't do the best job of holding things in them, tend to get rips on the bottom which would allow test strips to escape and can be a bit of an eye sore.
Thule Litter Bin:
Great design and large enough to fit the occasional diet coke or sandwich wrapper and the cap will keep my test strips from being liberated. The big draw back is that it sits facing the rear of the car, it's dangerous enough to test while driving, now I have to reach into the back seat to throw them out.
This one has some promise, but it will take up the passenger side floor and will thus need to be moved anytime someone else is in the car with me. Plus I'm not sure that the can would stay vertical as I'm zoom zooming, and that would basically defeat the purpose of the trash can.
This required some innovative thought; take a product designed to be an ash tray in a cup holder and use it as a garbage can. It would only hold test strips but it would not require me to reach in the back seat to throw them out and would be smartly placed directly next to my testing supplies.
Anyone have other ideas?