I have two of the 20 footers. Do check the actual weight of yours. There are different height units (one is called high cube and is taller) and weights vary. The selling yards usually have means of picking them up and placing on a trailer so unloading is the issue. Mine were both transported on and unloaded from a semi by a forklift ($500 and this was a monster forklift) inside one of my buildings (14 ft rollup doors at both ends for drive through) however mine were both full and quite heavy.
Empty, I am confident that I could safely load and unload one of them onto and from my 12,000 lb (max gross wt) 18 ft trailer (not deck above so would require cribbing.) I am further confident that I could secure it safely to the trailer and pull it with either of my diesel pickups at or above the minimum interstate speed of 45MPH with no particular consideration for excessive risk to the equipment.
Attempting to drive at or near the upper speed limit would incur those considerations and risks because it is like towing a parachute and HP requirements go up radically for each small increment of increased speed.
So much for my confidence in being ABLE to do it safely. A fair question is, would I go through all the effort (and expense of procuring the required materials) required to set up to do it and the doing of it to save $250. I don't think so. If you didn't have all the required materials and equipment and had to buy any (or most) of it you could find the margin nibbled away to the point you were working for free or maybe even paying more for the opportunity to DIY.
Just for info:
You can move these things around on a concrete floor using some floor jacks on wheels (standard automotive floor jacks) You can jack them up at one end at a time with a pair of jacks at the ends of a beam you have placed transverse at the end. By jacking and cribbing you can raise the container pretty evenly up high enough to back a trailer under it. This requires a heck of a lot of running around and around and back and forth jacking, cribbing, moving jacks, lather rinse repeat, but is doable.
There is no really hard part except for the jillions of repetitions required to get it up high enough using this simple method. It would be wonderful if you had helpers and 4 floor jacks. Railroad ties make pretty good cribbing but other arrangements can be made.
For heaven's sake, if you are thinking of involving concrete blocks in the process, first take out a big life insurance policy in favor of someone you like. Oh, and the helpers need to be able to pick up a floor jack and lay it down at least at the height of your trailer deck, either single handed or with another helpers assistance. They need to be able to stack the cribbing (like playing with Lincoln Logs on steroids.)
Readers Digest synoptic versioin: Pay the $250.
Pat