Nassau has a lot of excursions and all moderately priced. We spent the day at the Atlantis resort and had a nice time there. The locals are very friendly, car service and tours are available at a great price. You can save a few dollars booking your tours directly rather than on the ship.
Grand Turk has a small shopping village alongside Margarita ville, which is the ONLY source of food or drink on the island. Not one shop sold soda, snacks or anything other than extremely overpriced T-shirts & sportswear. Other than the beach, which was nice, there is margarita ville & drinking only. This stop was the only place that didn't charge any of us up.