Free applications means it is authorized to be free to use by the user by the developer.

Some developer devoted much of their time to develop applications and therefore they have to charge the user for using the application.

User would have to purchase a license to authorized themselves to use the application.

However, some of the application pirate cracked the application illegally, user can use it without paying the developer.

But this does not mean that it is a proper way to use the application as it posed a risk to be infected with the virus or trojan that might be inserted by the pirates especially for the Android where the security is not that good yet.

The big problem is user does not know that their personal data like contact, sms and web surfing data can be stolen by these trojan because they did not feel damaged caused physically.