Very similar to what I am building. I have most of the steel, bought when it was a buck a pound. I use my cut off wheel to cut the material. I probably need to pick up a few more pieces of steel. And yes, there is some labor into it. But I think so far its less than $200 of materials. I will probably spend another $100 in materials. I also trash picked some carts I got the casters off of. A few minutes with a cut off wheel and they were liberated for this project.

On a side note, I had a co-worker who built one out of pressure treated 4x4s and unistrut. Held his Nash Rambler body while he did all the work.