Once you are on the island, there are a few ways to get around. The first way is to rent a car. You can rent from a number of agencies, such as Avis, Budget or Hertz or a local agency like Discount Car Rental

Depending on how long you visit for, the type of car you get, and other factors the price for the rental can vary. You don't need 4-wheel drive unless you plan on using bad roads, or some of the roads in St. John. Gas on the island is a bit more expensive than it is in the USA. Another thing that is very important to note that though St. Thomas is a territory of the United States, driving is on the left side of the road, like in Great Britain. The reason for this is puzzeling because St. Thomas used to be a territory of Denmark where they drive on  the right. 

You could also rent mopeds or scooters while you are on the island, but since the island is relatively large, this can sometimes be impractical (and suicidal).

There are some bus routes on the island, and there are a lot of cabs, but this can get expensive if you continue to do this the whole time you visit. St. Thomas is a very hilly island.

The roads are poorly marked and the islanders drive with reckless abandon. Use cabs because they are everywhere.