I am planning to purchase Nokia Lumia 520

I am planning to purchase Nokia Lumia 520, but it doesn’t have a front-facing camera. Will this make a difference if I do not use internet on phone, or in making Skype calls?

—— Not having the front-facing camera can only be a disadvantage if you use Skype to make a video call, as the other person will not be able to see you. You can still do Skype voice calls.