A few weeks ago, I ordered a new SnugTop tonneau cover ($1200) for my '08 Ford Ranger and a bed extender ($295). I week after the order was placed, I was notified that the manufacturer does not make the most popular model I wanted for my truck. I called the manufacturer in Tustin and they explained that particular model when flipped 180° on the tailgate tends to partially block the view of the tail lights. The manufacturer objected to the ruling by some government body, but decided to drop that model.
Rather than blow it off, I studied the desired model (above) and visualized an inexpensive (OK, cheap) solution that would sit under the tonneau cover and keep stuff (mainly groceries) from sliding around in the bed of the truck. (No, it doesn't flip over and lay on the tailgate.)
I took a few measurements and headed off to Lowe's to see what they had. As luck would have it, I found some 2" ABS pipe (1.5" ID), elbows and caps ($50) plus two 3' strips of 1/2" aluminum ($7). I secured the 'extender' to the bedliner sides to make it stable and removable (2 screws). It's only a $50 solution, but I'm pleased with it. Hope you like it.