Re: Facebook ads
If you've ever advertised via Google AdWords, it's a similar concept. You pay only when users click on your ads. There are a few big differences though:
Depending on the goals of your campaign, Facebook ads can be a great way to get your brand in front of thousands of users at a very low cost. But keep in mind users on Facebook generally are there to socialize, not to purchase or navigate away from Facebook.
Re: Facebook ads
Facebook's ads work much like Google's, you will set your preferences and then be charged every time someone clicks. You will have new options with FB ads... you can advertise your business page on FB or you can advertise your website, depending on where you want the click to take the reader. My experience with FB ads is that they get expensive very quickly, you just have to establish how much you are willing to pay to get each click. $0.88 adds up fast when your target is "narrowed down" to 25,000,000 people.
Facebook ads are also cheaper than google ads
Facebook ads is still generating people money but a lot has changed. They have added new features and got rid of some to give people a more enhanced experience.