Hi, yes actually I tried exactly that. It cost me $60 / customer, which is over my lifetime value so I discontinued advertising there.
Here's my stats from the attempt: http://www.bemmu.com/stats-from-advertising-candy-japan-on-r...
Things might be different now, the page was less optimized back then. I might try again later, but I'm really hoping Reddit would just lower their minimum daily spend. Right now they have no advertiser there at all, I'd love to advertise if it was just a tad cheaper.