I have a used Navionics 3G911XL3 Compact Flash which was removed in working condition from a RayMarine C-series chart plotter. The only reason that I'm replacing it is that I needed a map chip that included Mexico's Baja peninsula and the Sea of Cortez. As the map shows, this chip starts just below the Sea of Cortez and goes to Ecuador. On the Atlantic side, it covers from approximately Tampico, Mexico to Panama to Venezuela.
Note that the date on this chip is 2003. Don't worry, the charts down there are rarely updated, so this chip will suffice just fine. As always, use your eyes and common sense, as some of the charts that are used to create this chip are from the 1800s! But they're the best that exist.
So, save yourself some big bucks and buy this instead of a "new" chip that probably contains the exact same charts. I used this for years on the Caribbean side and had no problems.