Garmin allows one chart subscription with the base price of the Blue Chart set. Additional 'chart areas' were around $99.00 USD when I last checked.
I am set up with the chart area for Tampa - New Orleans. If you are only planning on sailing in your local area, then select that one. If you travel; spend your money wisely.
I just picked up a Garmin 72 H yesterday to replace my Garmin 76 which disappeared during our last regatta. That unit does not have charts; however, it outperformed my Garmin 76 CXs during field testing yesterday against two other Garmin hand helds and my handbearing compass. Word is that it has the new antenna.
Bottom Line - make sure your gps is running the latest version of available software and check it for accuracy. During the US Sunfish Midwinters we found the 76 CXs was twenty degrees off at .5 nm. I am sure after it failed the field test yesterday that I need to upgrade system software.
Gets some buds together with their gps units, grab an accurate hand bearing compass, and compare the MOB bearing and distance. For example - find a football field - shoot the bearing between the goal posts from the goal line. See how your MOB data compares.
...a two beer project...