They come in primer, and need painting to match the colour of the vehicle.
I did it with my 1.8 Tonga project last early this year.
I had trouble finding an exact colour match, so unfortunately I'd painted the fog bezels in the incorrect colour, and didn't want to do them again in the correct colour.
Wherever is the cheapest. I found a pair new old stock on ebay, which cost me £20 for both. Being an LR trim part, they are quite expensive from LR, about £35 each IIRC.