Why can't you change package name without paying?
Now I'm sure you know, but if you don't know, package names aren't just for looks. Package names must be custom for every APK, or else if you try to download 2 or more APKs with the same package name at the same time, it'll end up not letting you use the older ones you've installed.
Please change it to be a free feature, or at least just append a random number to the end of the package name.