This is the kit I use:
Meguiar's(R) Smooth Surface™ Clay Kit, G1016, Kit | Meguiar's.
Comes with a detailing spray that doubles as a clay lubricant. Has a lot of clay and is easy to use. I've used it 3 times now and works fantastic.
I agree about a rotary and pad, that sound like a good way to burn your paint or send clay flying around the garage.