You can buy the CD and program your own cards or buy preprogrammed cards.
BUT there are differences, not in the charts but in the licensing.

Preprogrammed cards can be used in any Gamin GPS, but you can't copy them so
only one unit at a time.

Cards that you program from the CD can only be used in the GPS units that
they are unlocked for. Garmin allows you two units per unlock code.

A very large data card will probably hold the entire East coast.
You need to look at the Garmin site to see which chart regions you need and
compare prices. When you go to buy them, search the Web, you can find much
better pricing than Garmin offers. Also try eBay, used preprogrammed ones
come up there.

wrote in message
oups.com...
Am now thinking about a chartplotter, got some good info from group.
Thanks. Questions:

If I go with a Garmin (I'm thinking maybe the 376C) and wanted good
detail covering the entire East Coast and the Bahamas, including the
ICW; what would be the total cost using the CD and purchasing the
needed unlock codes? Would I also have to purchase extra chips; any
specialized hardware/software? Is it possible on the 376C or another
Garmin unit to buy the charts pre-loaded or on pre-programmed chips?
Would this be cheaper, and is the information the same in quality and
detail? Are there any advantages or disadvantages? How up to date are
the charts when you purchase the unit, does Garmin update them on a
periodic basis, and what are the costs associated with updating?

Thanks again for any help