I don't think anybody has a liquor licence in the DR. As suarezn said, you just open up, but the liquor and cerveza and sell... (don't forget that for any disco/night club in the DR you've got to have lots of "waitresses" there, otherwise the clientele won't come and the bar/disco next door would get the business).
When I had a small nightclub/disco in Higuey, the kickbacks involved amounted to about 1500 pesos per month - a bottle of Chivas to the local co****l, and about 150 pesos a week to the patrol guys for "gasolina" and "cena". They didn't show usually more than once a week.
Now, this is not Bavaro/PP/Cabarete/Boca Chica, there are also Politur guys and Marina de Guerra, so it gets more expensive.