For a natural dark brown shade that will effectively blend with grey hair, I recommend the Garnier Nutrisse Creme Permanent Hair Dye No. 4 (Medium Dark Brown) available for R85—it's known for its nourishing properties and long-lasting color. Another great option is the Garnier Nutrisse 3.6 Darkest Auburn Brown Permanent Hair Dye for R149.99, which also provides excellent coverage and a rich tone. Lastly, there's the Professional Hair Dye Tint Double Coverage Coloring Cream in 3.0 Dark Brown for R149, which is formulated to offer deep color and impressive grey coverage. These choices will help you achieve the natural look you desire while ensuring your hair feels healthy and vibrant!