Sam's Club offers its members the Suncast 7x7-Foot Cascade Storage Shed, model no. BMS7790D, for $679 plus about $51 for shipping. (Non-members face a $68 surcharge, so grab a 1-year membership instead for $45.) That's the lowest total price we could find by $70. It features resin walls, metal roof shingles, a double door, and windows.