There are a couple of great places you could purchase one mail cart for instance Global Industrial or maybe you could try Office Depot as well. Both places would surely accommodate your needs.
There is no brand of mail carts that are better then any others. The best thing to do to make sure your cart stays together is to buy a custom built mail cart.
You can purchase a folding shopping cart online. You can purchase the cart on Amazon.com at www.amazon.com/Folding-Shopping-Cart-Liner.../B000LPFUG8 or Walmart at www.walmart.com/ip/4-Wheel...Folding-Shopping-Cart.../.
The best place to look would be nextag.com. They provide the most options for you to find a rolling cart, depending on the size you are looking for and the use that you have for it (industrial or mail) this site would be your best bet to find what you are looking for.
There seems to be a lot those type of carts for a person to use. Grundorf Road-Runner Collapsible Cart 300 lb. load capacity is one example of such a cart. I think it folds up for you when you use it.
One can purchase cart furniture at sites such as Furniture Cart, Ongar Furniture Boutique, and The Furniture Store. One can also go to a site such as eBay, where people, sell their used items of Cart Furniture.
You can find a rolling utility cart at any of these industrial supply and equipment stores in Chicago; Crown Industrial Supply, Ametric Supply Co., or ToolSavings Llc.
Nothing they are the same
You can purchase a folding hand cart from your local Sears or Ace Hardware store. You can also purchase one online from the Amazon website and have it shipped directly to your house.
There are a number of websites from which one can purchase a service cart. These sites include Amazon, Harbor Freight, Northern Tool and Rubbermaid Commercial.
One can purchase a cheap printer cart from a number of stores. Such stores are Wayfair, Paperstone, Viking, Brother, Overstock, Argos and Euro Office.
mail carts have no doors
One can purchase a welding cart from online stores such as the website Amazon and the bidding website eBay. Alternatively you may purchase welding carts from a catalog store like Argos in the United Kingdom.