Website cost depends on the amount of work required to design, build, test and integrate the project. A one-page informational website is fundamentally different from an ecommerce store or customer portal.
What to consider
Key factors include page count, custom design, content preparation, product data, payment integration, user accounts, booking, multilingual content, APIs, migration and ongoing maintenance requirements.
A useful proposal should explain scope and assumptions rather than forcing every business into the same package. Clarifying requirements early reduces surprises and unnecessary development.