We got a taxi from the airport to the Sonesta, it's literally a two minute ride but it ended up costing $15 (4 times we did it, pretty much a set fare)! The Island itself was quite cheap, can't really remember how cheap drinks were but they weren't too expensive. The airport can be quiet at times if you've got abit of spare money I'd recommend booking a flight over to St. Barths for the day on Winair, the approach is fantastic. Saying that, St. Barths is very expensive so if you don't want to spend alot, don't bother going!