Coloring Gray, creatively!

I have dark brown hair, on the warm side, and a growing number of grays.
i want to color the GRAYS, maybe a nice fun purple or something, but do not want to really significantly change the color of the rest of my hair or explicitly "MATCH" the grays to the rest of my hair.
is there a way to do this, either at home or a salon?
what do i ask for, or look for on the box?
I am essentially a haircolor virgin, (got highlights once or twice over a decade ago)
thanks!!