When your son gets older and doesn't want to play with them anymore this is a neat idea
Hot Wheels Display Ideas to DIY - Moms and Crafters
IKEA Hackers: Ribba Hot Wheels Display Case
Custom, Hand-Made Wall Mount Hot Wheels Display, Inside of a Radio Flyer Wagon Bed, Can Also Be Used For 1:25 Scale Models by CNSwholesale on Etsy
DIY drawer organizer project ~ 48" wood laths super-cheap at Home Depot and the store will cut them for you. So simple!
Hot Wheels Boys Wood Truck Display Case by RusticNickNacknStuff
Hot Wheels Display-links to more carded displays
Hotwheels display. Wood blocks with track and car shoot added.
Hot Wheels Display Cases, Matchbox Display Case, Johnny Lightning display and other 1/64th scale die cast car display
Car displays organizers More