Liat and InterCaribbean both have one way flights around $100.00 right now for when I am looking in January. I'm not sure how reliable either airline is but there was some talk on here of Liat being a better experience for some recently. Our group is looking at spending the night in San Juan and then taking either of those airlines out first thing in the morning. We are choosing early morning flights in anticipation if there are any problems there will be more options to get us to Tortola.