Alright i am looking for a trailer and realized i dont know shit about them and didnt realize all the different kinds.

Do trailers require a title and to be regestered because im finding a lot of 'homemade' ones on craigslist.

Do they have to be insured?

Do they have the maximum weight stamped on them somewhere or is there a way to find out?

Should i get a dual axel or do they have single axles that are strong enough to hold more?

Im looking to be able to pull up to a fullsize truck but mostly cars and 4wheelers so i dont need a super long one and no 5th wheel.