You could also just buy slatwall (the stuff retail stores use) from a fixture supply company. You'll get a wide range of finish/color options and pay about $30-$40 for a 8x4ft panel. You can cover all 3 walls of your garage from floor to ceiling much cheaper than using these other products. If you are worried about weightload, you can usually ad alumnium inserts to the grooves for an additional charge per sheet (might bring the total cost to ~$70 per sheet) but you probably don't need those everywhere.
The hardware for slatwall can also be had much cheaper as well. instead of paying $10 per hook for the gladiator stuff, you can get a whol bag of hooks for that much. Check the store liquidations (like Linens and Things) of which there is no shortage nowadays. They'll sell you the hardware by the cartful for pennies on the dollar. You can probably also buy their slatwall as well.