You will not get a 3br for rent on the beach at that price. Metro starts at3000 in the country club.
There are - to the best of my knowledge no 3brs for rent on the beach - although there may be villas on the beach in Guayacanes at that price. Drive there and check out the signs and there may be some opposite Talanquera hotel.
I know of lovely apts for rent (3br) in your price range but one or two streets back from the beach but have sea view (at the moment until they build in front!!!)
pm me for more info.
Matilda