You can usually look on stores' websites around where you live to see if they have them. I know Walmart carries a brand, Home Depot had some last I checked as well. Coroplast can usually be found in home improvement-type stores or sign stores (I usually get mine in Rona or Home Depot).
You can usually put some kind of wording like cube shelving into their search engine to look to see if they have anything. Try and make sure that all of the pieces have 9 squares along the side, in recent years they seem to get more cheaply made with larger spacing.
As for stands, you can use almost anything that fits the cage and works in your space. I built mine out of extra storage cube grids, you can use a large table, you can build your own out of whatever.