If you are going to buy it and start from scratch, the cost would be more than many want to invest. That is why many shops can charge high prices to do it for you. I have all of the stuff in my shop and I use it all of the time on my stuff and for some others, so my investment gets cheaper each time. A good bottle of rubbing compound is anywhere from $ 40.00 to $90.00, depending on what type and brand you buy. The buffers are around $180.00 to $300.00 for a real high quality unit. On top of that, you have the different things that you would use, such as masking tape, clay bar, and waxes to finish with.
Check out places like
www.Autogeek.net for prices on buffing equipment and polishing materials.