Groupon offers the Ogrow 15x6-Foot 2-Door Tunnel Greenhouse for $209.99 with free shipping. That's the lowest price we could find by $32. It features a waterproof PVC cover and ventilation windows.

Also available is the Ogrow 2-Tier 12-Shelf Walk-In Greenhouse for $144.99 with free shipping. That's the lowest price we could find by a buck. It features steel shelves. Both deals end May 19.