Cabinet toe kick is certainly cheap enough to replace. However, that does take some effort to remove the old toe kick and install the new. If the damage is slight, why not try to repair it?
A lot of damage to cabinet toe kick is from water. Maybe the dishwasher leaked, or maybe you repeatedly got crazy with a wet mop. If the damage is not bulging out, but rather discolored, grab some stain and give it a shot.
Toe kick is typically a thin piece of veneered wood. That means that the attractive finish is extremely thin and doesn’t go through the entire strip of wood. Think of a thick strip of wallpaper glued to a thin piece of plywood. You can lightly sand the veneer, but if you get too aggressive, you will burn through it and not be able to repair the damage. So the key here is to be gentle about it.
Water damage will appear as white stains. Use fine/medium sandpaper and remove the staining. Then get some stain and stain the piece of toe kick. It might be tricky to match the color, but stains are made in a multitude of colors.
Once you stain the toe kick, you can try to match the finish. When the stain goes onto the wood, it will look somewhat dull and a little lighter than the surrounding finished wood. When you finish the piece, the color will come out and it will be a closer match.