Quite a few people report their results on r/gamedev if you sift through the postmortems although they're a bit tough to find, some recent ones I've seen:
> Reddit ads for Next Fest. $100 spent, 230k impressions, 1k clicks, ~5 activations, costing us $20/user.
Interesting! Thanks for this. I'm worried that my space (personal finance) may be especially difficult since people are curious but extremely skeptical - there's a huge trust barrier.