Lot's of hurdles to opening a bar by the beach. First, land 60 meters from the highwater line is public and cannot be built on without special, hard to obtain, approval from the government. Second, much of the beach area with sufficient users to justify establishing a bar is already within the control of a resort project and/or has well established bars already serving it. It may be possible to buy one of the bars already serving Sosua Beach, for example, but it would be expensive and you would have lots of competition.