Okay, this might be totally out there and not suited to this audience but......
We did a stop in St Maarten with another cruise line back in November. Have you seen the videos of the huge planes flying right over a beach as they land on an island? I've always wanted to experience that and Maho Beach in St Maarten is the place to do it.
We walked about 15 minutes into the town (a little raggedy in spots but felt totally safe) and stood at a marked bus stop on Back Street, the second street in from the beach. The public buses are just regular looking minivans but they have a card in the front with a destination and the license plate has a B at the beginning. Flag down a van with "Maho" or "Mullet" as the destination and confirm with the driver. I believe the price was $2 US for adults and $1 for kids and American dollars were fine. The drive took about 20 minutes and we found it fascinating to drive across the island, stopping every few minutes for all kinds of folks; ladies with their shopping, giggling teens in school uniforms, senior citizens and workmen heading home. We helped make change for a group of four who only had a ten dollar bill.
When we got to Maho we asked the driver and he showed us where to go and pointed out the place where the buses would pick up for the return. It was a five minute walk to the tiny beach that was squeezed between the road and the water. There was also a bar where you could grab a drink or snack while waiting for the planes to land. We had checked the flight schedules on line the day before and timed it to arrive about 20 minutes before two full sized planes were due to land. The schedules were also posted at the bar.
Standing on the beach as the 737 came in was just amazing. It really did feel like we could have reached out and touched it as it swooped overhead. Even a sudden downpour that came in just before the plane and drenched us didn't dampen the fun. We stayed for the second plane and then hung out on the tiny beach for a bit before heading back to the bus stop. The return trip was just as interesting and easy. (We made sure to leave plenty of time to get back to the boat and had cash for cab fare if the bus didn't work out for some reason.)
I know not everyone would be comfortable with this sort of plan, but for us it was one of our best stops ever and came in at a grand total of $12!
Here's a really bad video of the landing. (My camera wouldn't focus because of the rain). But it still gives an idea of how it feels to be there.