When are you going?
Isn't the ferry port in Dixon Cove? Anyone?
If so, Barefoot Cay is quite close by. (I can't picture where the ferry port is) But it's not inexpensive. ($130+/nt.) Nice though and they have a small on-site restaurant for guests only.
Barefoot Cay
Some of my friends stayed at Coconut Tree in the West End. They're older, basic, but decent. My buddy had a single room with small refrigerator for $35/nt. Posada Arco Iris also looked pretty nice.
Although it would mean a longer cab ride both ways, you would be close to multiple bars/restaurants for food and the cabs congregate just across the street from CT. They also have one of the two West End food stores there, the other, Woody's (bigger) is a block away. Sundowners Bar just across the street is a local hangout and Mavis & Dixies - about 2 blocks west - serves great food on the water. Under $20 pp. also. It's a pretty safe area too, there's a lot of tourists milling about.
If you've got an early ride back for the ferry though, you might have to make arrangements to get picked up - I noticed a couple of mornings there weren't any cabs before about 8AM. Not much open that early either, but you might be able to get a quick breakfast across the street. (it's a yellow building, can't recall the name) Food service was epicly slow also.
Downside is that the West End is not exactly close. And the opposite direction from the ferry. You'd actually have to double back past the airport in the morning. Maybe 1/2 hr. or more, we never went directly to Dixon Cove from the West End so I'm not sure.