In my opinion, facebook is probably the best platform for you to advise your business locally. Facebook gives you options to target people from specific demography. Also, facebook has a better conversion rate than any other social media platform.
Which FB ad is going to be of much benefit; A country-wide ad or localized one? Is this your question. Well, it lot depends on where your potential customers are. If your customers are country wide, you will get a better reach. If not, go for a local one.