Reason 4 to live in Santo Domingo: Moderately cheap living costs
As an island, you would expect the Dominican Republic to be much more expensive than other countries. This is true on the one hand, but it depends of course amongst which countries you compare the Dominican Republic.
Compared to most cities in Europe and North America, the Santo Domingo would be the cheaper alternative. But also in Latin American cities Santo Domingo is rather a cheap place to be than an expensive place and ranks somewhere in the middle. And if you would compare the Dominican capital with many other Caribbean islands, you will probably find not a cheaper capital to stay.
These prices from the screenshot are of course just average prices and vary amongst the different neighborhoods in Santo Domingo where you want to live. Generally spoken, these prices are affordable and somehow fair. Depending on your lifestyle (of course), you can live relatively cheap in Santo Domingo with these basic costs of living (housing, food).
I wrote it earlier in the second reason, that the Dominican Republic and Santo Domingo acts as an air hub. A strategically good position amongst Europe, North America and Latin America makes it easier to transport and import goods from other countries to the Dominican Republic.
Same holds true for water transport: The Dominican Republic imports many foreign products through a lot of strategically important harbors in Santo Domingo, Puerto Plata, Bayahibe and Punta Cana.
A supply of foreign delicatessen and other products is guaranteed and much cheaper than in a lot of other Caribbean islands. The country profits therefore from its good location in the Caribbean and you as a final consumer will notice it.
Other than that, agriculture is stable and an important factor to keep the costs of staple food low. Rice, fruits, chocolate, coffee, vegetables, meat etc. are available for an affordable price. Depending on your diet, you can save some money and a lot of calories.
And for all the sinners it can be happily stated, that you will probably find nowhere in the world cheaper rum and cigars than in the Dominican Republic. Tobacco and sugar cane are produced on the island as well and are probably typical what you would expect the Caribbean to be.