Hi All -
Not photo specific, but FB advertising is a cornerstone of my architectural events business, and we find very good ROI on well-constructed ads. I've run a few small tests to sell prints, but didn't optimize the sell-through, so ultimately the test was unsuccessful (i.e. no sales), but my clickthrough was promising and should scale.
A few things to look at. Using Slobodan's example above, the ad is far too general, and I'd be curious to see the target audience in detail. The ad itself doesn't really speak to a specific goal. Were you trying to sell prints, or make contact with potential architect/developer clients? That's important and should be reflected in the ad. (The result of better targeting is a lower cost per click, and a more qualified audience). I also think Slobodan's sample size is too small. If I was trying to sell a $299 print, for example, anything up to an including a $150 cost per acquisition would be a raging success, and somewhere between $150 and $298 cost per acquisition would require an analysis of ROI on time involved. Conceivably, if I had a good list acquisition and sell through system, and good customer loyalty, I could argue that even paying OVER a one-time sale cost would be worthwhile.
Does all this make sense? Sorry to pick on you Slobodan, but your example is in the thread and being an MBA type, I figure this might make sense to you and you might have more thoughts on the subject.