Can I transfer an app to somebody else without having them to pay for developer enrollment?
Yes, the receiving company will need an Apple Developer ID and membership of the Mac and/or iOS Developer Programs.

Part of the process of enrolling involves agreeing to Apple's terms of service and other legally binding agreements. Without agreeing to Apple's agreements, the receiving company will not be able to participate in Apple's App Store or Mac App Store.

It is possible to have applications associated with your Apple Developer ID but not participate in the App Stores. However, those applications will not be eligible for sale through Apple.