What does it mean? Not that much really. In the app store apps that are Free will now have a button called “Get” instead of “Free”. This is due to the fact that a lot of free apps have the option for in-app purchases and people were complaining about it being confusing. So go out at GET some apps.
Keep in mind there still is not a way to use the VPP program to make in-app purchases. This is something Apple is going to have to deal with one day, but I thought they would have already.