Did you go to the website I listed for Moorings? Prices vary widely depending on the time of year and vessel chosen.
Do you want to use mooring balls, drop anchor or stay in marinas at night? Anchoring---free but not an option in all places
Marina Slips ---$50 and up/night
Are you going to sail or motor? How much are you going to run your generator? Diesel is about $4.25/gallon
Airfare is another huge variable. Are you going to prepare the majority of your meals and provision accordingly or prefer to dine at the numerous beach bar/restaurants? Do you intend to eat burgers or lobster? How many people are going? How many add-ons are you going to want such as water toys etc...? Without much more information from you, budgeting is a dfficult question to answer with all of the unknown variables.