Replace bumper is about 500-1000 depends on cars

We do not know what kind of damage it is. It is hard to tell you just replace bumper or need more work than that.
You should ask repair shop the cost for just replace and paint a bumper cover. You will have an idea on the cost.
Insurance issue: you should ask insurance company about their policy... Most likely it will show on carfax that the car has been repaired in much later time. You can always keep your record on the repair to show future buy what the damage was. If I was a buyer, I would not care about a car had bumper damage and well repaired....