A boosted post is a post from your business Page that, for a fee, can appear higher up on your audiences News Feeds.

The fee depends on how many people you want the post to reach, the payment depends on the number of impressions the post gets with time; according to Hootsuite. Although, there are some things that you should consider before boosting your posts:
Never Boost a Post if You Are Unsure What is Your Goal!

There are several reasons to boost your post, you just have to define what is yours. For example, your goal can be to get more ‘likes’, to get more blog traffic, to give away free product, increase brand awareness etc. Everything is easier when you are absolutely certain what your goal is. It all starts from an idea.
Know Who To Target
You can choose to boost the post to the News Feeds of people who liked your Page, and also their friends, or select a particular audience through targeting. There are various targeting options ( Location, Gender, Interest, Age). Ask yourself again: „What is my goal?“ Targeting ALWAYS must be based on your goal. Boosting your post is going to be effective only if you have found the right audience. Don’t mess this up. Think about it over and over again until you get it right.
Test The Timing
When boosting a post you should keep in mind what time of the day to do it. Right timing depends on your audience, content and your overall goal, but mostly of your audience. The audience is the main factor. It’s not a bad idea to test it so you can see what time of day works the best for you. Once you know when is the perfect time you should focus only on that period. That way you can be more effective.