How much is your cost per install?

[willzeng]

If you are running a market campaign, how much is the cost per installation?

I just made some test in Admob, and it turns out to be $0.5~$1 to have one installation of a free app. I wonder how about paid ones? What's your case? How could people get the advertise fee back?

btw: Some Admob guy says conversion rate 1.5%~2% is normal, and I verified it. Since the lowest bid is $0.01/click, so...