There is a good sale that end on April 30th. $30 less is not too bad for what the card as to offer.
You got to be sure that you're unit can run those cards. There is a document to verify that:
Compatibility Guides | Navionics
Platinum Plus | Navionics
This is some examples of what you can get:
http://i1094.photobucket.com/albums/...ps1c585d60.png
http://i1094.photobucket.com/albums/...ps1c585d60.png
