Unless your startup is targeting teenage girls in third world countries, you shouldn't be trying to simply optimize for low CPC. You need to be thinking about

Unless your startup is targeting teenage girls in third world countries, you shouldn't be trying to simply optimize for low CPC. You need to be thinking about traffic quality and conversions. The beauty of a fluid marketplace like Facebook Ads(or AdWords, for that matter) is that the cost of traffic will eventually approach its value. The people clicking these ads are not going to be spending a lot of money on your site, that's why the clicks are so cheap. If you try this same approach targeting, for example, middle aged women in the US, who have much more purchasing power, you can expect to pay closer to $1 per click. Note that this post doesn't say anything about conversions or sales. And if you think you can build a successful business around dirt-cheap clicks from African children, well I've got a few million guaranteed visitors to sell you :)