Unfortunately, your income of $962 a month won't qualify you for a resident visa so you will have to leave the country every 180 days to get a new FMM tourist permit. You should take that into consideration as you choose a place to live.
I'm not an beach guy so I can't comment too much on which coastal places to check out but some poster here do live on the waterfront and can offer more ideas. The popular ocean-front locations will always cost a bit more but there are some more off the beaten path locations.
$962 will be a little thin to live on (the clue to that is that the minimum income for a resident visa is about $1200 USD a month - that is the low end of comfortable) but I do know a fellow that lives here on a pension of even less and doesn't appear to suffer too much so it certainly can be done.
Big factor: Do you speak Spanish? That reduces costs immediately and opens up more options for everything.