I emailed Market Samurai as to why there was a difference between Google Adwords "Average CPC" and Market Samurai's AWCPC. I got a reply from Rachael. Here is a summary of her explanation: The "average cpc" in adwords is just a baseline price that google throws out there - you still have to bid on the keyword - the final cpc might be higher or lower than the "average" baseline. So, when you hit the "Analyze Kewyords" button in Market Samurai, one of its functions is to "bid" on all those selected keyords for you. The resulting AWCPC for a keyword is their calculation of what you would pay if you had the #1
ad position for that keyword. I hope this helps to clear up some confusion

As far as adsense publishing goes, remember that you only get 68%