Clients might think a designer is stalling by not sending an immediate quote, as if the designer wants to figure out how much is available. But the designer is by no means guaranteed the business, so it makes more sense to offer a quote as soon as possible.
Thing is, no project is the same and every client differs. A designer can’t give an accurate quote until a design brief is in place, and that doesn’t happen until after talking.
This design pricing formula does a little to explain the complexity of cost.
Or if you’d rather not give your email, here are a few relevant resources on pricing your skills.