Hello, Patricia, and welcome to Airforums.com!
This IS the place to find out the answer to any and all questions regarding Airstreams that you may have.
My first comment is that, to my knowledge and experience, ALL RVs leak, Airstream or otherwise. The leaks are a maintenance issue, so start reading up on the many threads that talk about them. In fact, when people on here first buy an Airstream, we try to always caution them to look for leaks and seal them up first, BEFORE they start doing anything else to their trailers.
Secondly, your post is only looking for advice on what the differences are between the various models. When you have decided on what you want to buy, you don't have to go far to find a good source to buy one. We have our own busy Classifieds!
Other members know that if they want to offer you a trailer they own, this is not permitted on the Forums, and they should put an ad up if they want to sell, or contact you off-line.
Another issue that is an important one to understand is that many communities do not allow living in trailers that are parked on private property in a residential area. This is important since if your DO make it your full-time abode, you will want to connect the trailer to services such as electricity, water, and a sanitary sewer. Make very sure your community allows this before you go and install those things.
Good luck finding the trailer of your dreams, and be sure to post lots of photos of it when you do!