I've already answered this in one of the other thread, below is the answer you are looking for:
Well, there are many ways to earn from FB pages.
1) Brand Promotion: Tie up with any brand and promote the product. May be make a video and tell your audience how good the product is.
2) Affiliate Marketing: Register with any affiliate marketing network like (Amazon or Ebay) and sell their product.
3) Content Network: Register with any content network like (Viralaux) and promote their content.
There are pros and cons to all these methods, so you must choose which one suits best for you. Personally, I'm using Viralaux to make money from my pages
Hope this helps!