Trailers can range anywhere from $300.00 dollars and up.
Yes most states require trailers to have titles. You can check with your local DMV to see if your state requires you to have a title.
Yes trailers have vin numbers. Most manufacturers put the identification on the trailer in two different forms. Some manufacturers weld the vin number to the main frame, some stamp them, they also use a sticker vin plate that is voided if ever peeled off.
There are many types of trailers out there. Here is a list of a few well know types, cargo trailers, enclosed trailers, horse trailers, stacker trailers, equipment trailers, utility trailers, landscape trailers, race car trailers, toy haulers, RV trailers and many many more. There is pretty much a trailer for everything.
Trailers come in many different sizes. Most common sizes are in the even numbers like a 4x6, 5x8, 5x10 and so on. Trailers can be built all the way up to a 53' Semi trailer.
Yes aluminum trailers are lighter than steel trailers. Aluminum trailers are typically 5% lighter than steel trailers give or take the size.
Used trailers can vary in price just like autos. It will all depend on the size, year, make, model and even color of the trailer.
The most common lumber used for open trailers is pressure treated pine. Pine is really strong and durable. Most manufacturers out there use pine.
Fifth wheel trailers are easier to handle in the way of backing them up and turning tight radiuses. Some people prefer to use fifth wheel trailers versus tag trailers. They feel that having the tongue weight centered over the rear axle of their tow vehicle puts less stress on it.
Yes you can connect two trailers together. You will need a class A non commercial license along with an endorsement on your class A drivers license to tow doubles.