Grocery prices are NYC or Wholefoods-like. Plenty of less expensive places to eat (see link for ideas). You seem to have the right outlook - eating and drinking will cost you, but only as much as you allow it.

http://www.tripadvisor.com/Travel-g147365-s504/Grand-Cayman:Caribbean:Cheap.Eats.html


Snorkel air just tastes better than canned air...