kauai tours and tour prices

Hi,
I am trying to figure out how much all the activities that we want to do are going to cost, ( approximatlley). I have serched on the web a bit and have found whale watching tours from $100.00 plus to $60.00. The $60.00 dollar tour is through captain Zodiac, any one herd of this one. Is it better to book on line or wait till you get there. Also tours to the Na pali coast?? $100.00 plus?? is that worth it. Any reccomendations on tour operators and good prices?? Is it necessary to have a guide if you do the bike ride down the canyon?
thanks Lynne

Read this book:

http://www.wizardpub.com/kauai/kauai.html

I'm currently using this book to plan activities (among other things) for my trip to Kauai in May. They do some nice, seemingly unbiased reviews on operators, too.

I personally haven't used the Kauai book, but I have used the Oahu version, and it was the best guide book I have ever read for Oahu. Do some searching online, and perhaps read the book reviews at Amazon.com, and you can see what others have to say about it as well.

yes, it is most excellent....we bought it on our 2nd day on Kauai....on our first day we went to eat at this one place and it really sucked....when we checked in the book they said don't eat there...it really sucks....