I am actively running only one Adwords campaign right now on a sponsor site that pays $30 PPS. What is now working for me is to offer only the minimum bid of $0.05 per click, and hope that everyone else does the same! The conversion ratio from Adwords was great for the first three months, but dropped down out of the stratosphere after that. For the last three months on Adwords sales, I figure I've been paying $19 for every $30 sale.