How much does ceramic coating typically cost?

It is almost impossible to say because there really isn't a 'typical', but you should expect to pay upwards of £500 for a new, medium-sized car.

The cost of a ceramic coating depends more on the condition and size of the car than on the actual coating. Applying the coating is just the final stage on the process where your car is polished and make as near perfect is as economically viable. Therefore, the cost of the service is, polishing and preparation plus ceramic coating, with the former often being the larger part of the cost. Some companies will advertise the cost of the coating without including the cost of the preparation, making them seem much cheaper.

A used car will be more expensive than a new car, a small town car will be less expensive than a mini-bus, and a 3-year coating is less expensive than a 10-year coating.

If you want to know how much it will cost, the best thing to do is ask. For the detailer to get an accurate quotation, they will need to do an inspection, or at least see photos and video of the condition of the car.