I only run a handful of auctions on this ID. 

But nonetheless.  I still think some auctions do contribute to driving sales for me.  Whether they sell or not, I can view (in real time) buyer activity via inkfrog and time and again loss leaders appear to be worth the investment.

BUT ... that being said, I refuse to "gamble" $1.50 a pop for auctions more generally (aside from as loss leaders or a highly desirable brand at lower start price than usually sold) - I would never list anymore just to achieve a single "sale" from the auction, as buy-it-now listings on this ID eventually sell through buy-it-now - I wait it out in this particular IDs market.  It all sells, eventually, some higher $$, some lower $$ than first listed.

Other markets, tell a different tale. 

IMO differs based on markets, and which segment in the market your goods attract.