Not exactly: The developer pays $1 + app cost, they in turn will receive 70% of the app cost from Apple. So the effective cost per user acquisition for a $0.99 app is $1.30.

1000 apps installed per day = $1000/day

How do you generate the coupons?

These coupon codes aren't the same as the ones from iTunes. These are generated by TapZilla and redeemed within the app itself so that it can inform us which user from our service downloaded the application.