Virtual Reality (VR) and Augmented Reality (AR) are kind of apps whose development costs varies greatly. There would be no easy way to tell a cost without the specific requirements, but the hour rate from us (drafteq.com) is $18-$25 . For a simple VR app showing an environment where user is walking, it won't take more than 2 days hence cost wont be more than 200 dollars.
I am working in VR amd AR for a year. You can have a direct chat with me . Just ask for VR person on drafteq.com by chatting from bottom left corner of the site.