Now I am having size envy! (I mean 3D printers )
I have not used commercial 3D printing houses preferring DIY. Most of these places will provide quotes based on your STL file, the intended materials and the desired print resolution. As a rough estimate, printing cost varies from $3.50 to $5.00 per print hour plus materials. Some of the larger or more complex prints may take days.
With regards to material selections, PLA is much more common and is available in a wide variety of additives/blends such as wood, metal, carbon fiber.... For harsher environments such as high heat or chemical resistance or strengths, PETG, Nylon and other specialty filaments may be required. If the chassis is not subjected to much heat, PLA may be a good choice.