Seeking advice on dry weight / towing capacity

If you just want to get into this for a couple years before upgrading, it might be worth looking at used pop-ups or A-liners, as suggested. I saw a 4 year old A-liner on Craigslist the other day for around 5 grand.
To find out how trailers keep their value, just look around on the net for both new and used prices on the same camper.
In your case, the fiberglass eggs are probably the best value, but can be pricey.