Ask for a module breakdown
Discovery, interface design, mobile screens, backend services, administration, testing and deployment should be identifiable. For a booking product, distinguish account creation, availability, booking, payment and notifications. Each module needs a description of the supported behaviour and acceptance criteria. Clarify which services or assets you must supply.
Identify exclusions and recurring costs
External APIs, hosting, developer accounts, content entry and data migration may be billed separately. Support terms and future updates should also be clear. Check the assumptions behind estimated effort and whether tax is included in the commercial figures. Avoid treating an illustrative budget as a binding quote for a different product.
Compare the same delivery
Align the brief before comparing totals. An offer that excludes backend work or quality assurance cannot be compared directly with a complete delivery. Check milestones, payment schedule, code ownership and how changes are approved. A trustworthy quote gives you a practical way to verify progress and to resolve disagreements about scope.