Assuming you are traveling from the U.S. --
How are you planning to enter the BVI? By water taxi? Ferry? or by plane?
How are you planning to return to U.S.? By water taxi? Ferry? or by plane?
Last time I checked the Virgin Gorda airport was still out of commission for runway paving.
When you plan to travel may guide your possible choices for testing to re-enter the U.S. (the busier it is, the more likely BVI HSA may not be able to return you test results quickly enough).
Test at home to submit to portal - $? depends on where you are in the U.S.
Travel/Health Insurance (if needed) - $? depends on the cost of your trip (travel portion) and the age of travelers (health portion).
Portal fee - $35
Test upon arrival - Rapid (usual) $50, PCR $70
National Parks Fee - $10
Customs - 10% to 20% of goods you are bringing in, if any
Taxis in BVI - Estimated prices can be found here (scroll down to Taxi Tariffs links): https://www.bvitourism.com/taxis
Test to return to U.S. - there are a host of options with different pricing. A PCR test from BVI HSA will be around $70. Concierge style testing will be more. DIY is another option (such as eMed).
Departure fees - will vary depending on your mode of departure travel.
I welcome updates and corrections!