I've been acquiring SaaS users for <$10 for awhile now at around 50 cents a click. I find the ads extremely effective if you know what you're doing and target the right demographics. That being said, the conversion thing makes total sense. There's lots of little tricks that have worked like make a campaign with over $100/day on ads and you get prioritized over the little fish and then lower it right away so you're still prioritized in their display algo but you aren't spending at that amount. If your adspend really is 100 start it higher like 1000. Lots of little tricks you can do that will tweak the system to your advantages. but buy paying for likes or showing ads to people who like candy crush or "insert corporate page" you'll probably burn at over a dollar a click to your site and most of those will bounce hence leaving an ineffective campaign.

The thing is though even if it's slightly working it's probably cheaper then AdWords, so for larger budgets/non personal it's a great way to get the same amount and comparably the same targeted traffic for less capital.

Also if the ads are so horrendous please explain the numerous ad hackers that have done TeeSpring campaigns making 100k by targeting niche at scale. Sorry just some musings on facebook ads from someone who's seen people do it wrong, and has made money on the network for myself and clients.

It's pragmatic, with the right intent, niche, offer, and funnel. Custom audiences greatly increase your chances as well, and massive retargeting with "users that aren't truly retargeted but you have their data" Probably not by throwing generic money at it and expecting magical high value users/sales.

P.S. Agreed! re: StumbleUpon is SO HOT for their ads. I wish their were more native advertising networks. StumbleUpon and Facebook are hot. Twitter seems to only work for certain niches with custom cards for optins but even then it seems it's over a dollar per click and generic web traffic or the plethora. StumbleUpon CPM seems to be some of the best ratios out there, and clicks are really cheap sub $1.