This "As Seen On TV" product even fits around your seat belts and moves with the seats if you adjust them!
Promising review: "I have to admit, my expectations weren't very high. I thought it was more of a joke when my husband got this for me for Christmas. Little did I realize it would be one of my most favorite gadgets ever! I don't know if I realized just how many things went missing in my seat gap. It has really saved a lot of things from disappearing into that black hole. It was easy enough to fit into my car and it's soft! It's just like an extension of my seat, except it fits every curve of my seat!" —Tessa Forbes
Get a pack of two from Amazon for $24.99.