Depends directly on the size and the number of curves. If you've never applied film before and, it's a piece that is large, don't bother, you'll never make it happen. Pay. Those folks will do it correctly without inducing installer issues....hopefully.
The bumper is too complex for a first timer, spend the money, you'll be most happy that you did, Matthew. A mirror cap, maybe or a completely flat piece (that doesn't exist) but not a bumper or larger.