[Taxman]

Don't be surprised if there's no such thing as an off the shelf paint that precisely matches your silver car.
But you can always get lucky. Silver is very difficult to match.

That said:

APS Tower Paint Company, Spray Max, Aerosol Spray Paint, Custom Mixed Spray Paint
Automotive Touch Up Paint from PaintScratch - Order Pro Grade Paint - PaintScratch.com
Touch Up Paint and accessories | AutomotiveTouchup