Something that works but you don't mind it getting banged/beat up.
But please, for the love of all things holy, don't leave a firearm in your vehicle unattended unless it's in some kind of secondary lock box. Too easy to bust a window and make off with a firearm...
What about them making off with your vehicle?
I save myself the aggregation and expense of replacing windows and leave the vehicle unlocked, >half a tank of gas, and the key in the ignition.
What about them making off with my tools?