Yes, Sam's Club has similar shelving units too, some with casters for easy rolling:
http://www.samsclub.com/sams/s...
At one time I had PVC shelving units that I used in my greenhouse and years later when the greenhouse was dismantled, the shelving units were put to use on the deck but I haven't seen the pvc type shelves available anywhere in awhile ... could be I just haven't noticed because I've not needed them. The good thing about the hard plastic/pvc was they didn't rust so they were nice for use outside. They came in white or black:
https://www.amazon.com/dp/B001KYJQMI/
https://www.amazon.com/dp/B0083ESFA2/
I had the white ones but I painted them hunter green because the white was just too stark for my taste. The only thing about the ones I had is the shelves had a small lip so when I watered my plants, the water didn't drain so I had to drill holes into all the shelves to allow for drainage.
