Mines about as cheap and simple as it gets.
I've got the tow strap, large wrenchs, hammer, PB blaster, oil, p/s fluid, tube of grease, duct tape, gloves, paper towels (doubles as tp!), etc. in the plastic tote. I put a couple of "eye" hooks in the back of the seat to keep it in place with a bungee cord.
In between the tote and the sub is a small tool bag that has all of my socket wrench goodies, flash lights, mechanic's mirror, etc. I shave my head so I am always keeping my headwear options plenty. So the bag doubles as a hat rack!