You’ve probably seen companies with Facebook pages that have hundreds of thousands or even a couple million page likes & followers. It makes them look credible, but it’s not because they are going viral every post. The secret trick is that you can actually just run ads from the Ads Manager with “Page Likes” as the optimized goal. They’re super easy to set up, and will just run perpetually gaining you followers and page likes in the background. For a US audience only, you can expect around $0.20-0.25 cost per follower/page like, while with an international audience, you can get as cheap as $0.002 per follower.
This is worth doing, since it really helps make your pages look more legit. I like to set up a campaign spending ~$30/day and just forget about it. Check out this walkthrough on how to set up Page Like campaigns: