RE: Jeep Trailor???
In my opinion, a class at like a Community College would definatly be worth it. Yes, you can learn to weld just fine on your own, but in a class you'll learn stuff that might take you several years to even discover by doing it on your own. It will also give you someone to ask questions and get 'professional' opinions from...like which welders are good and which you should stay away from, for your specific usage.
If you do go that route, something like an Arc Welding class is the direction I would go in. Once you get that down, you can weld with any machine. It really teaches you how to control the puddle and the arc better than any other type of welding (besides welding with a torch, maybe). After you get that down, MIG, TIG, and all that other stuff is a piece of cake!
So yes, I'd say it's more than worth the time and money if you have a good school you can take the class at!!