At what point is a PPC campaign not effective

I have been dabbling with Adwords PPC for a while now. Promoting mostly Click Bank products, but have tried a few CPA offers as well. My question for you is when do you cut bait on a campaign? I have some campaigns that have a 3%+ CTR but don’t convert. Basically every product I have tried doesnt convert well enough to make much money (if any at all).
I have done ALOT of Adwords research and feel my campaigns are fairly solid, but I am still not making any money to speak of.
Typically when I launch a campaign I would throw the same amount of commission as advertising, and determine if profitable from there. Meaning if commission is $50, I will advertise for $50, if no sale I drop the campaign.
Lately I have tried to improve a few of my better […]

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