1. Do you mean the star field or the other lighting?
2. Here is a pic from the front looking towards the back. The projector is hidden in the back soffit. If you look in this picture you can see the hole it shoots through.
3. The sky is the limit as far as cost. I paid roughly $200 for the material to create my screen. My first screen was just a 4x8 sheet of mdf that I painted and it was great.