Marina space on the out islands, like the Abacos, isn't cheap. The last place I docked my 30 ft. Hunter now charges $500/mo. for the off-season (Sept-Feb) and $800/mo. for the rest of the year. I now keep my boat on a mooring for $200/mo.
Good plan to take a sailing class! As far as the wife goes, if she is also serious about cruising, she should take classes with you. At sea you will be a team and she will have to have to stand her fair share of watches. Don't scrimp on her education.
Good luck and have fun!
If I have to rely on my wife at sea I might as well put a gun to my head right now.