Two things stop us showing a price, and neither one turns into a made-up number.
The model cannot be printed as it stands. The quote screen names the issue in plain words and offers a hand quote instead. The hand quote costs nothing.
The engine is not answering. Slicing needs a service outside this website. When it is busy or unreachable the price panel says so and offers a hand quote. It never shows an old price for a model nobody just sliced.
Tell us the part and what it has to do, by email, phone or the notes on a quote, and a person prices it and comes back to you. A model we could not price becomes a request in the studio's own queue, so it is held by somebody rather than lost in an inbox.