For $100 a night I assume you typically stay in the standard rooms at Rockhouse, off season. There are some good options in this thread that will fit your budget. The economy rooms at Catcha are a great option, but might be smaller than what you are used to. The Garden rooms at Xtabi are in that price range, as well (maybe even lower).
I would also look at Mirage. All rooms are have a water view and you can easily find one for <$100 off season. There is no restaurant or bar on property, but there are plenty of local establishments and markets withing walking distance. Plus, the hotel is owned by a longstanding Jamaican family (same owner as Charela).





