You need to determine how you are going to use it and how often. If you buy new you need a lot of money. If you buy vintage, you may need a lot of time and talent to bring it back to reliable operation. If you have limited skills and tools, buy the latest model trailer, in the best condition you can afford and start using the trailer as soon as you can. The rest will develop as you change your goals and improve you trailering, touring, and camping skill over the next couple years.