How to level my camper WITHOUT moving it or using blocks?

4 ton bottle jack for $20

This little jack will raise your axles. Put pieces of wood under the jack and position it under the spring shackle. Raise the axle and slip your boards under the wheels.
I'd suggest you get some type of jack for your trailer. If you ever have a flat, how are you going to change the tire? There is also maintenance that requires a jack. I know some folks hire everything out but there may be situations where you need to perform the task.