I've been running various ads for SongBox for about the last 36 hours. All the ads are carrying largely the same copy and exactly the same images.
After 2 days here's the results
Reddit (Reddit only been running for about 12 hours)
Spend: $3.34 (Note - US dollars)
I think what's working best for me is Google Display - however I'd really like to hear some other analysis from folks on here.
EDITED TO ADD
On Google display I targeted only USA, UK, Canada, Australia, New Zealand and most countries in Europe. I also targeted by household income in the top 40%.