all inclusive carribean vacations

We are having a destination wedding in November next year. While I know that many people will not be able to come due to time and money, I am trying to make it as affordable as possible while still being a nice trip. I don’t take many vacations and when I do it’s usually a close-by car trip. What is the normal amount of money people spend if they are going to the beach (say in the Carribean or Mexico) for 4 nights/5 days? This is for hotel and airfare. I am looking at some all-inclusives like Sandals or Beaches Resorts(which are more but it includes food and entertainment) and some hotels where people could be on their own as far as paying for food. Can you please give me an thought of a reasonable amount so I can try to choose a place that will increase attendance as much as possible while still being a gorgeous wedding?