Really depends on the product.............PPG has a line called OMNI ( comes in Base coat/Clear coat and single stage ) and is way Cheaper then the DCC Concept single stage -DBU-DBU Deltron Base Profesional Line.
I would have to call my jobber to make sure, but I would guess 1 Gallon of color (Black), catylist and reducer(single stage) would be around 150$ to 400$ at the most depending on what way you go BC/CC or Single stage.

SprayTech