(iOS Dev)
What is your revenue model? Ads? Price? DLC? It makes a difference. As well as the market.
In general though, I have found that the best use of your time and money is making a good demonstration video on YouTube (which improves all of your future posts/messages you distribute anywhere), and a PRMac release ($20).
I'm not endorsing PRMac, but I have had great success with it, and in the long run it helps your search rankings.