EPC stands for Earnings Per Click. Some affiliates (and advertises) new to the industry sometimes confuse this, thinking this means the offer will pay X per click. This unfortunately is not the case.
EPC simply means the average Earnings Per Click. The idea behind EPC is to give you an idea on how the offer is performing compared to other offers on WOW Trk.
For example: If the offer has an EPC of £0.80 and you were considering running a different offer which is very similar and the EPC for that offer is £0.60. You might decide you would be better off running the offer with an £0.80 EPC (however remember this is just an average and doesn't mean you will achieve an £0.80 EPC).