Facebook Flyer Testing – Not worth it.

I found about facebook flyer which is cpm advertising at Facebook. Their min purchase is $50 and $2 CPM. I bought 30,000 impression spread out 3 days for my aviation social networking site. Within 24 hours, 48% displayed according to facebook stat and I got 1 sign up. ROI is just sucks. Not worth it at least to my site. I could use $60 for better ROI. Can anyone tell me who has success with Facebook Flyer?