There is a company called LKQ I use to find used parts when I can’t find a new part or the customer is trying to save some money. I have been able to find body parts such as the mirrors and bumper covers in the same color as the car I’ve been working on through them for fairly reasonable prices. You can also try going through traditional junkyards.
The next option is buying a new bumper cover. Then having a body shop paint it to match your car. Generally the price to paint match a bumper run about $300. Plus however much the part costs. You can find bumper covers on places like Amazon and have it delivered to your home or to a body shop. If you purchase a new bumper cover they come unpainted and you could just install it like that on the car, but will have a black bumper cover.
Also underneath the bumper cover you have an impact absorber, usually a piece of hard foam. This supports the bumper cover and is an important part to replace if it’s ruined or missing. You also have a steel bumper under there as well. Both parts can be purchased used or new through a junkyard, LKQ, or Amazon.