Is it actually possible to get clicks if you set the CPC to one penny for greatly targeted ads? They would be targeted to visitors interested in a certain game on Facebook. (Think farming!!) If not, about how low can it be to get clicks?
I don't believe it would be possible for CPC but perhabs CPM. 1000 impressions for a dollar and a 10% CTR which is needless to say extremly hard... you are going to have some mind blowing ads to get that high of CTR.