I have a Porter-Cable 7336/7424 random orbit buffer that I've used for several years. I got it at Lowes. It doesn't come with buffing pads or backing plates - I had to get those separately.
It's variable speed for different needs and works wonderfully for buffing paint. Since this is new to you, you'll want to stay with a random orbit unit as they make it
almost impossible to damage the paint.
Head over to
Autopia and poke around a bit. There's more polishing and detailing information on that site than you can digest in months.