In retrospect, yeah, I feel like an idiot for bidding the suggested bid. I've run pretty substantial campaigns on both facebook and google adwords though, and always had good experience bidding somewhere within 20% of the bid.

I also maybe was slightly duped by this statement after setting moderately restricted targeting:

"You have selected market area or demographic targeting options. As a result, you will receive significantly fewer impressions."

But thanks, and for anyone reading this, don't advertise paid apps on Admob, and don't bid anything higher than $0.10 if you have a small campaign.