there are sunbeds provided by the hotel you do not have to rent them, Alicia S is right , they take them away each night because the tidal range would risk them being swept out to sea at high tide, just ask them , they are very helpful. :)
all you have to do is ask the security guards at the entrance to the beach to bring you sunbeds over and they will no problem. I usually tipped them a colon or 2 and they then of course remember you and make sure you have what you need on the beach. There is also waiter/drink ser vice on the beach so you never have to leave. honestly the customer service outweighs any of the small negatives the resort may have!
The resort did not have any. There were people selling independently that you could rent from but I am unsure if this was available every day. There are many available at the pool though.
It did not look like there were any sun beds for rent on the beach
Get an answer from Margaritaville Beach Resort Playa Flamingo staff and past guests.