600$ is mainly for companies small or big. the modular character approach exists in other software and games, can be great for populating some place with generic people, for character or team controller by the player you will need something that’s make it appart and looking great. UE4 have morph targets system that could allow you ot have many different faces from one base. Or you can almost do it manually using some program like Make Human exporting different heads and body shaps than combining them in a modeler do dynamically inside UE4.