You will find that different geographical regions have different purchasing habits.
For a fact, consumers in Asia are more used to freemium (in-app purchase) models. Which is something you may wish to consider. For example, if you are selling a game with multiple levels, you could offer the first 20 levels free, and the rest to pay for.
If you reach out to me directly and tell me more about your applications, i maybe able to be of more help and give some pointers.