Provide me with a CAD drawing for a 3D printer (very simple small item)

I need to use a local a 3D printing firm to produce a CAD Drawing for simple plastic item for a project I'm working on. The project doesn't require engineering precision (photo attached, near enough is good enough)I guess it would take 15 - 20 minutes work (or less) for somebody who knows what they're doing. I would be happy to pay £50 to receive CAD drawings in a format suitable for a 3D printing co. PS. When considering the photograph, dimensions can be plus/minus 5%, there's no need for the slot in the vertical fin, the underside is shown below the actual item that requires a 3D drawing, the appearance of the underside is irrelevant (can be completely flat).