When trying to determine the value of a service or product there are two different value perspectives.
There is the value perspective of the consumer, of what value they are going to get from a product or a service and how they value what they are going to get.
The other perspective is the value that the business creates. How much time and effort was put into the creation of the product or service?
A broken clock is right twice a day. But if the service is providing the time, the fact that the clock is right and a client gets value at that point does not mean there is overall value in the clock. There is no value in a broken clock.
Spend just as much time determining the value you are building as in determining the value your client is going to receive. They are two very different things.