I have had both and the trailer is considerably less expensive than the class A. How much? The variables are too much to say. What size of each are you looking at? Gas or diesel class A? After having both for some time, here are my observations.
The trailer is less expensive to purchase but if you get a large one you will need a large expensive truck that will be the vehicle you drive once you get somewhere. Most trailers have smaller refrigerators and microwaves. Trailers have considerably less storage and smaller tanks. The trailer I had was very inexpensive to maintain. I had a 30 foot trailer.
The Class A was more expensive to purchase - I purchased a used diesel. It has a lot of storage. The refrigerator, microwave and storage tanks are large. It is more comfortable driving and living in. It is considerably more expensive to maintain. I purchased a used one and got an extended warrantee and it had more than paid for itself. The normal maintenance on a diesel is much higher than it was on the diesel truck we used to pull the trailer with.
If you are tight on funds, I would go with the trailer and the truck.
