That's in Cuba not the DR. The bar people here are the same as back home. In most restaurants and some bars a 10% gratuity is added to your bill. However, this is distributed among all the staff. So the person who served you might wind up with a few pennies. If you received good service from your bartender or waiter, give him a few $$$ especially if it was not included in your bill. As far as the other stuff, perfume etc. the money is more important to feed their families. If they want perfume, they can buy it at the store.