Walmart offers the Sterilite 18-Gallon Storage Box 8-Pack in Gray, model no. 18158208, for $39.68. Opt for Site-to-Store pickup to avoid the $4.97 shipping fee. Although we saw it for $4 less in January, that's easily the lowest price we could find, as most merchants charge at least $11 for a single box. Each box measures 24" x 18" x 16" and features a snap-on lid.