Artwork question

[Slncapri]

I have a company that has seen my artwork firsthand and is interested in having me do a drawing of thier project car for them to post up in their shop. They would likely be displaying this drawing with the finished car. My question is how should I go about pricing the drawing and presenting the company the drawing as professional as possible. I would like to get return busines from them and other area shops.
My artwork is all hand rendered with pencil then marker and pastels with a little airbrushing. I plan on framing and matting the drawing when finished in a 24 x 36 frame. I have some of my artwork posted on the thread titled "NEWBIE" if any one needs to see my work. I will be putting alot more effort into this job than any of my other drawings to hopefully aquire more jobs from area shops. I just enjoy the heck out of drawing and seeing the faces of people when I show my work. Any help is greatly appreciated, thank you in advance.