The cheap-website trap
A low headline price usually excludes strategy, original design, content structure, integrations, testing or support. That does not always make it bad, but it makes comparison misleading.
What changes the cost
Page count, product volume, custom functionality, integrations, copy, migration and approval speed all affect the real workload.
What to ask before hiring
Ask for the exact deliverables, revision structure, ownership, renewal costs, platform fees, launch responsibility and post-launch support in writing.