0% intro APR for 15 months on purchases and b… Discover it Chrome Calculators How we make money
VOATLAS
How to Pay for a Rooftop Cargo Box

How to · Auto

How to Pay for a Rooftop Cargo Box

Get more storage for your family road trips without paying for it all upfront or dealing with interest for over a year.

VoAtlas editorial Updated · 3 min read
Typical cost $750 before anything else
Across the 0% window $50.00/mo 15 months, no interest

How we got that: $750 spread evenly across the 15-month introductory window on the Discover it® Cash Back. Checked · at the bank Carry a balance past the window and the standard APR applies to what is left.

Owning a family car means you are always short on space. Between strollers and gear, the cabin gets cramped fast. Buying a cargo box in late August or September is the smart move. Retailers want to clear summer stock before winter gear arrives, so prices usually dip when the weather starts to turn.

A solid, aerodynamic box helps with gas mileage and keeps the wind noise down. It is a big one-time cost of around $750, but it saves your sanity on long drives. You can negotiate the price at local outdoor shops, but for online retailers, timing the sale is your best leverage.

This is not free money. If you still have a balance after the 15 months, the standard interest rate kicks in on whatever is left. Pay the $50 every month to make sure you are clear before that clock runs out.

The steps

  1. 01

    Measure your clearance

    Check your garage height and roof rack spread. An aerodynamic box is sleek, but it still adds height. Make sure it won't hit the garage door or block the trunk from opening fully when you lift the hatch.

  2. 02

    Wait for the late summer slump

    August is the sweet spot for these. Families are done with summer camping and haven't started thinking about ski trips yet. Look for end-of-season sales to shave some money off that $750 sticker price.

  3. 03

    Use the 15-month window

    The Discover it® Cash Back (Discover) offers a 0% intro APR for 15 months on purchases and balance transfers. If the box costs $750, you can pay $50 a month and avoid interest entirely during that time.

  4. 04

    Check the mounting hardware

    Not every box fits every crossbar. Some need specific adapters or claws. Verify your car rack type before you buy so you aren't stuck with a plastic shell that won't stay put on the highway.

  5. 05

    Store it properly

    When the trip is over, take it off. Leaving a cargo box on all year kills your gas mileage and wears out the plastic. Keep it in a cool, dry spot to make sure the locks don't seize up.

  6. 06

    Check the card terms before you commit

    Every figure we publish for the Discover it® Cash Back carries the date a person verified it against Discover and a link to where they checked. Intro windows and APRs change without notice, so confirm the current terms before applying.

    See Discover it® Cash Back terms →

Common questions

Does a cargo box affect gas mileage?

Yes, even the aerodynamic ones create drag. You will likely see a drop of 2 to 5 miles per gallon. It is the price you pay for not having a suitcase in your lap.

Can I go through a car wash with it?

No, do not do that. The brushes can snag the box or rip it right off your roof. Take it off or use a touchless wash if you must clean the car.

Are these boxes waterproof?

Most are water-resistant, meaning they handle rain fine. They are not dry bags. If you are driving through a massive storm, a little moisture might seep in through the seals.

Do I need a roof rack first?

Usually, yes. Most cargo boxes mount to crossbars that run side-to-side. If your car only has side rails, you will need to buy the crossbars separately before the box can be installed.