Walmart carries these for < $13 - stores very nicely, has 4 sizes and enough leverage to break a lugnut free.
I store it in my front compartment like this:
Buddy Ray - Atlanta
Jayco Eagle HT 26.5RLS
Ford F150 Lariat, 3.5L V6 Ecoboost
Max Tow Pkg, 36gal tank
Reese Sidewinder and Reese Titan 16k hitch