The cost of advertising on Facebook depends on what you’re advertising – and to whom. The more advertisers approaching your targeted demographics, the more you have to pay for each click or impression.
When you’ve created an ad you set a max bid – the highest amount you’re prepared to pay for a click. This will then decide how much you pay for your ads (although it doesn’t mean that all clicks will be at your max bid.)
If your max bit is too low, however, you might lose the competition and not get any clicks at all. And again, the highest bid can differ quite a lot from segment to segment. In some areas a click on your ad only costs a few dimes whereas in others you may have to pay a few dollars for the same thing.
You also put a budget limit on your entire campaign to have a control of what you spend.
For more information, read our overview of Facebook advertising cost.