Home-Complete HC-4202 Walk-In... https://www.amazon.com/dp/B01GDVVZY4?ref=ppx_pop_mob_ap_share

I picked the greenhouse up on Amazon. It's very sturdy and pretty darn cheap for a walk-in size. I did slightly modify mine by omiting the lower shelves. This gave me larger niches to fit the size trees that I have and does not effect the sturdyness of the construction at all. Hope this helps!

https://www.amazon.com/gp/product/B01GDVVZY4/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1