I disagree with most answers and I'll tell you this: don't put any money into advertising. Apple's algorithm is a machine. When you stop pushing downloads, your downloads go back to where they're naturally supposed to be. You should buy traffic if you know that each user brings you more money than what it costs you to get the install. On a different matter, I don't believe launch is as important as other people say. Ok you're going to get a spike of downloads for maybe a week or two but that's not long term business. You need to constantly improve your marketing with new updates, try new stuff out, change your screenshots, keywords, icon, title, change category until you hit it. When I launch an app (not a game), I can get anywhere between 500 to 10 000 downloads per day for the first week and then it naturally goes down to 100 to 1500/ day. After that I try new stuff out in my apps to get the downloads up. If you're new in this business don't waste money in buying traffic