So at a $2.99 "fair" price point as mentioned in the post, how many copies does he have to sell to break even (assuming 4 days of development priced at $2,500/day contractor rate)?
(1 * .99) * .70 - (4 * 2500 + 99) < 0
(10 * .99) * .70 - (4 * 2500 + 99) < 0
(100 * .99) * .70 - (4 * 2500 + 99) < 0
(1000 * .99) * .70 - (4 * 2500 + 99) < 0
(10000 * .99) * .70 - (4 * 2500 + 99) < 0
(14574 * .99) * .70 - (4 * 2500 + 99) = 0.78
The answer is => 14,574 downloads would give him $0.78 profit, before taxes. (In that time, he would have earned more than $13,000 for Apple.)