From a PetaPixel post about how one wedding photog made $18,000 from a single shot:
All too often I hear photographers make excuses for why they should undervalue their work: “It only took me an hour to shoot.” “It’s only a half-day.” “I’ll do this one for cheap so that this client will give me more work later.” “It’s not my regular work so it’s not that big a deal.” “I’m not going to do anything else with the shot.”
Forget all that. It’s not about you. It’s about the value that you’re delivering to your client. There’s a lot of mediocre images out there in the world. If a client wanted one of them, they could use one for a song. If they want you, it’s because you offer something special. Don’t be afraid to charge for your specialness.