I found the Helix mentioned above on sale at Amazon for $297.96 But in reading the reviews it appears to use it's mapping program you have to also buy additional cards....
The HELIX 5 CHIRP DI GPS G2 is also AutoChart Live capable. AutoChart Live uses GPS and 2D sonar information in order to allow you to map basically any body of water, revealing its most up to date depth contours. Keep in mind though, that this feature can only use LakeMaster and Navionics charts as support, thus you’ll need a LakeMaster or Navionics card chip in order to use it. Also, the unit is compatible with Zero Lines chips, which offer zero line contours for most bodies of water in the U.S. and Canada.
Come on in boys! The water is fine!