I read somewhere that there's some kind of material you can buy that has tape on one side and keeps things from sliding around in the back., What are some good materials for this?

 

Don't know about tape... I use a bungee to hold my subwoofer in place. Same if I'm carrying my jumpstart pack. There's a cargo net for groceries and such. On the bottom of the shelf there are several more tie down points, just flip the shelf over and you can use them.

 

I use banana boxes to keep my newspapers from moving around on me.

 

The carpet works mostly for me.
Go to the flooring dept. at Lowes/Depot etc they have a couple of kinds of anti slip stuff to put under area rugs.

 

could be Velcro tape? I use tie down straps and the tie down loops!

 

Many different products made with that description. You could Google something like "tape down non skid liner" or similar words. Or just go to your local hardware place and see what they have.

Me personally, I use a full length rubber mat. Keeps small things like grocery bags from sliding during normal driving. Anything that could become a deadly projectile in the event of a crash should be tied down.