I am Painting a Xbox 360 casing for my freind... Im making it a halo like theme with a rustic old look. I preatty much have the faceplate done. It took me about a day, and Im guessing that it will take another 2 or 3 days to complete the full case... How much should i charge him with the full case (Gonna look like the faceplate) and have a detailed Halo logo on the side... I have a picture of the faceplate to give you more of an example

There are also many custom chases available of Xbox in market.

I am Painting a Xbox 360 casing for my freind.

And were you commissioned (asked) by this "freind" sic, or did you offer or volunteer for the task?

I was asked by him after giving a casing to my other friend for his birthday. He offered me $20 for the full case,but i know that's not very realistic.

Does $20 cover the cost of the materials?

Because if this is something you are trying to get off the ground as a money making hobby you need a few examples.