Rightline Gear

Rightline Gear is the North Carolina-based auto-accessory brand best known for its waterproof car-top cargo bags and truck-bed tents. Founded in 2005, Rightline's pitch is simple: you can buy a rooftop cargo box for $400, or a Rightline Sport cargo bag for $100 that holds the same amount of gear.

The cargo bags are 100% waterproof, strap to your roof via the door frames (no rack required), and fold flat when not in use. They're a staple among road trippers who don't want a permanent box on their roof.

Build quality is better than the price suggests. Not a lifetime product but they'll survive a half-dozen road trips.