Walmart offers the Reese Explore Rainproof Expandable Car Top Carrier for $32.99. Opt for in-store pickup to dodge the $5.99 shipping fee. (Amazon charges the same with free shipping for Prime members.) That's tied with our mention from two weeks ago and the lowest price we've seen. (It's the best deal now by $9.) It's water-resistant and expands up to 16 cubic feet.