They used have a free wifi 2nd floor in the food court but it was very SLOW then they stopped and locked it. But if you sit outside of the cigar store, free wifi at varies times. Also the store with green color I believe, they do give wifi if you buy something.
Otherwise, theres a internet service inside terminal A for a fee.
Nothingless, in DR nothing is free, you have to BUY to get free wifi!