Unless you fill your boot to capacity, storing things there usually means stuff slides around while you drive. These DIY cargo blocks offer a simple solution to keep boxes in place in the boot.
Instructables user imjasonc offers a simple, inexpensive, and highly configurable way to keep stuff from sliding around in your boot. All you need are some simple framing angles and some Velcro tape or strips. Just clean the surface of the angle for better adhesion and stick on a measured length of the hook side of the Velcro. You can build several for just a few bucks and stash them in your boot for when you need them.
Easy Configurable Cargo Blocks for Your Car Trunk [Instructables]