I want to start snowboarding, but I don't know..where to start? HELP!?

I want to start snowboarding, but I know it's expensive. I've lived in the Poconos my whole life, so I've seen a lot of people do it, and almost all my friends do it, so I wanna at least give it a try. Should I rent my fist few times? Should I go ahead and but equipment? I'm pretty sure that I will like it, and I can always return it. If I should but it, should I get it off ebay or somewhere cheap? Do I really need a snowboarding jacket and snowboarding , or can I use my winter jacket and snow pants? HELP HELP!