I’ve heard of this trick before, but never really got to play with it until recently… if you increase your CTR (click-through rate), you’ll decrease your minimum bid price.
Recently, I found a keyword that had 0 competition so I took an offer from CJ, direct to merchant (whose landing page stunk for the keyword), and was set at minimum bids of $0.50. After day 1, I increased my budget and was able to drop my bids to only $0.15. Day 3, I went down to $0.10 and still had 0 competition.
Day 3 the clicks remained the same as day 2, but look at that drop in cost! Too bad the event I was promoting ended, so my campaign was paused. But it was a huge learning experience – hearing about this and seeing it first-hand are completely different.