First my impression was that you were an affiliate. Now I conclude from you later post that you are a vendor. Am I correct? How many sales did you make?
$300+ per check is pretty good. I myself wasted too much time/money with adwords, right now i am also focusing on article marketing. Article marketing and organic SEO is very good with clickbank! PPC can be difficult since the majority of CB products pays under $30 and keywords are just insane high.