The reason for the price similarity is pretty simple... the single disc player is a Honda product (usually) and they can be found for roughly $200 on eBay... if you were to get a Honda 6 disc changer, be prepared to sell organs... as they run about $400-$500 :shocked: Being they are OEM products, they tend to jack up the price.
The Alpine unit (6 disc), brand new, goes for $279... and then $30 for the adapter.
You may want to try on eBay, they usually have Haynes or Helms manuals for sale for Honda's.
Also, if you have the Honda manual that may have come with the car, the last page in the book tells you how to go about purchasing a Helms manual.