Shipping containers are great but if you want some more open areas, engineered steel buildings can be had for really cheap. Also look into pole barns.
You need to do your own work though. Apart from the largest things like pouring a large slab or erecting a steel frame, you can do everything yourself with some pretty basic tools.
Those are going to be your cheapest options for permanent buildings. As far as trailers go, you need a tow rig as well. Again the only real option is you needing to do at least a little work or labor will kill the concept either way. For around 10k you could likely have a decent tow rig and trailer but you need to know what to look for, where to look, and how to maintain them.
__________________
boom
|