Just walk on the beach from place to place until you find one you like--that's what i did. There is an expensive place right where the boat docks that i think is mentioned in lonely planet--probably why it is expensive--but i would suggest finding some beach front place that will be cheaper.
I dont remember seeing any hostels. I stayed at a posada owned by this nice couple who cooked shrimp for us--but i cant remember the name. have fun.