In 1984 I bought an all aluminum 40', except for the two endcaps. I paid $275. for it, and borrowed a tractor-trailer to bring it home.(yeah, BORROWED). I couldn't get it to slide off the flatbed, so I called a wrecker company right around the corner and they came and pulled it off for small change. When I went to move it the next time, about 39 miles, I took a 65 foot mobile home trailer frame and cut it down to 40 foot. I left the axles at the rear, thinking the wrecker I had scheduled to haul it could handle the weight better than the two mobile home axles. (The container was loaded at the time). The wrecker made if about 25 feet before the hitch sheared on the tongue. So the wrecker driver just wrapped his cable and chains around the tongue and hauled it like that. I later cut that trailer down to a 20 foot steel decked one and sold it. The next time it got moved, it was loaded on a Landoll Trailer and moved to where it sits now. The most I ever paid was $100, and the furthest was the 39 miles.
It has seen better days, since the wooden floor is about rotten, but I still keep some junk stored in it. I can probably get more than I paid for it most any day, since it has about 3000 pounds of aluminum in it.
As mentioned, keep an air-gap open under it, as they don't like sitting on damp ground.
David from jax