It depends on what you want. You can spend a ton for a long lasting version or you can pay little and do it yourself.
Adams makes a great do it yourself ceramic. Ceramic Pro makes a 12 year version that you usually get someone else to do.
I had Ceramic Pro Kavaca PPF (which has a ceramic coating on it) done and Ceramic Pro Gold over the whole car. 4 layers of 9H and one layer of light.