I think this has a lot to do with what you are selling and the niche that you are in. In some cases, you might see a lot of ads on Facebook, but how many of these are working will depend. I think a lot of people go into Facebook advertising because they have been told this is the only way for you to make some money and to advertise online. Of course Facebook wants you to think this way because this is the method they can use in order to make some money. You need to take an objective look at your own business model and decide what is going to work the best for your needs.
Do not just go into Facebook because someone else is doing it. This process might work well for them, but they might be in the section of the industry that it works well for them. You could end up shelling over a lot of money if this is not working for you. In my experience, even though there are a lot of accounts on Facebook, most of these people are not even looking at ads that are on there. Facebook will count these as a reach, but you did not make any sales from the work.
So take the time to look at some of your market and see if it is going to work. Have others in your industry had success. If you find that this is a failure for most of them, it is probably a bad idea to try it out on your own. This does not mean that you cannot find some other social media sites that are going to provide you with a great way to reach the customers. Twitter can work, Pinterest. If you are using Facebook, make sure that you are using the right ads that will work for your business and not just a blanket policy that will waste a lot of money.
If you are not good with advertising and do not know how all of this is going to work, consider hiring a marketing manager. They can do all this hard work for you and save a lot of time.