... also on the transport. $290 is quite reasonable for a roundtrip from the airport. Would be hard to negotiate a better rate than that yourself. Some dive ops if you are arriving on the same day as other guests may also give you the opportunity to split the costs with others.
The other option to consider is to take a van to and from the airport and use the ferry for the crossing. That will save a significant amount.
The other option to consider is to take a van to and from the airport and use the ferry for the crossing. That will save a significant amount.