It depends what you want it for.
I have black false fur that I use for thatch. I paint it with yellow paint mixed with a few drops of glue (white glue for wood). The false fur "drinks" a lot of paint. No need to waste expensive paint, any cheap acrylic paint will do.
At first I was afraid that it would look too yellow, but when dry it darkened and it went light greyish yellow - just the colour of old thatch
but that probably depends on the orgininal colour of the false fur.