Moderate relevance and a bit higher click through seem to be worth a buck off the high bid price on some of my campaigns -
I've got running for a client in a hot space where the high bids are $7 to $10 bucks a word. I've found I have to match the high bid just to get above the fold - but then after a few days, the price we actually pay for the clicks is at least a buck, buck-and-a-half less if I can get click through over 2.5%.
But some of the competitors will pay anything - so bids can climb a couple bucks in a few days. A single deal landed from these key words will gross $100,000 or more. So, I'm guessing we'll see them in the $30 buck plus range very quickly.
Many of the competitors don't test ads, drive to general website home-pages instead of specific keyword land pages, and don't capture data. So, I'm assuming the secret to survival is winning that battle - though of course, they'll all catch on eventually. The irony is they are marketing agencies
