That is for tracking traffic source costs.
These are completely independent of what your offer pays out unless you are working on a CPA/CPI model. You won't be.
If you know the CPC that your traffic source is charging then switch to CPC and put that in.
Quite often you will be paying in a CPM mode and so there is no CPC, only an effective CPC that arises from your CPM and your CTR. In this case, you should estimate an average CPC and put that in.
Later on you can update it to be more accurate - e.g. you run a Decisive campaign and the CPC averages around $0.03. Actually, take spend and divide by clicks to get a more accurate value, e.g. $0.03122. Then put that value in for your campaign CPC so that the cost tracking is at least ballpark correct.
thanks zeno but im still a bit confused. I talked to a friend and I told them i was running my first campaign through POF and he said to click "do not track costs".Pof uses CPM but there is no option for that like you said so... should I estimate at this point because I am a complete newbie and trying to launch my first campaign atm so i wouldnt really know what to put for an estimate and im also curious why my friend said "do not track costs"
There's two options:
1) Don't track costs
2) Track costs using an approximate CPC (a guess!) and thus have cost tracking that is inaccurate.
In other words, you get inaccurate values, or none at all. The choice is yours.
You can change at any point in time and it will effect clicks from then on. So, you could always start with "do no track costs" and after a few days, you might find your clicks are averaging around $0.45, so could change the campaign to CPC and put that value in.
It is entirely up to you.