Once your ad is running, Facebook will provide you with detailed statistics showing who is actually clicking on your ad. You can then use this information to further refine your targeting to lower your costs, because you will receive more highly targeted traffic this way.
In the Facbook ad creation control panel you must create your ad first before you can target the audience.Facebook Budgeting
Start low, perhaps $10 to $20 per day. Facebook does not penalize you for starting with low amounts. The minimum is $1 per day. Facebook will show your ads even with low daily budgets, unlike Google.
As a rule of thumb, start the first few days bidding well below Facebook "s recommended highest CPC (giving just enough traffic to test the effectiveness of the ad while keeping your cost down). After that bid the highest recommended CPC for a few more days (giving the most traffic for your money). Then run the numbers to find where your bidding “sweet spot” happens to lie.
You can run multiple ads in the same campaign, and they will share the same daily budget and schedule.As you might expect, the best place to begin to learn about Facebook advertising is on Facebook itself. Simply log in to your Facebook account, scroll to the bottom of the page and click on the “Advertising” link to start learning all about Facebook"s recommended practices.
Various Other Ad Networks