This stuff works as good as the professional stuff ( I do finish detailing for a bodyshop) $10 at any place that sell automotive polishes and waxes.
DA is safer...rotary is for somebody that does it every day. Claybar is for somebody that lets their car sit outside and doesn't take care of it. You could do it for the first time but after that polishing with compound and wax (or spray wax if you do it every week) is all you need. In fact if you put a good wax ( 4 coats) on twice a year and spray wax very frequently then you will be good to go.