Lots of decked systems on marketplace… not worth it?

I have two child car seats in the back of my crew cab, emergency tool stuff, work tools and materials. I have a soft Tri-fold tonneau over the bed. During hunting season I may have firearms, decoys, and a kayak. Mostly I’d like to take all my valuable tools out of the cab and keep them secure. They’re about $900 on marketplace at the moment.