A couple older threads have been closed, so I'm writing here to give current information and directions to a decent option ON Paradise Island for Food and Liquor purchase.
Very hard to find, but there is a small shopping area in walking distance that seems to be off-property and with prices that are much better and also where you can find things that aren't available in the resort.
From Royal Towers, walk through the Casino and then follow sings to the Marina and walk through the Marina shops. Just before you come to Johnny Rockets (at the end of the shops) walk left and you'll come to a main roadway. There's a crossing just toward your left and then you're in the little shopping area. On the SECOND row of shops is a Bristol Liquors as well as a small grocery. Bristol sells wine/beer/liquor at fair prices. A mid-sized bottle of premium Gin ran us under $20. Cans of soda were $.80, vs. $3.50 on the resort. This area also has Anthony's restaurant, where the prices are slightly better than on resort, and a Dunkin Donuts (that we didn't go into.)
Given that package goods and regular groceries are impossible to find on resort this is a good option for those who don't have the time or interest to go into town. I figure we got pack the money we spent on the Gin and mixers in a single cocktail each on our balcony.
Munchies are also available our there at more or less regular prices, not $10 for a bag of Doritos.
Some guests we met said that they'd found a place that delivers groceries and liquor to the resort hotels, but we didn't get the name of the service. I'd be interested in anyone knows about this option.