Walmart offers the Camco RV Standard Battery Box, model no. 55362, for $4.88. Opt for in-store pickup to dodge the $4.97 shipping charge. That's tied with our September mention and the lowest total price we've seen. (It's also a current price low by $10.) Designed to protect the battery from the elements, this box features a lift-off lid, a durable woven hold-down strap, foot clamps, and stainless steel screws.