Understand the engagement model
A freelancer usually sells specialised capacity; an agency may also provide product management, design and quality assurance. A fixed-price quote requires a clearly bounded scope. Time-based work offers flexibility but needs regular budget and progress reviews. Decide which model suits the uncertainty of your project rather than assuming one is always cheaper.
Compare equivalent responsibilities
Check whether discovery, design, backend work, testing, deployment and support are included. Ask how many people contribute and who coordinates them. Seniority can affect both the rate and the time needed to solve a problem. Compare expected accepted output and handover quality, not the daily rate alone.
Make assumptions explicit
Document dependencies, exclusions, payment milestones and the process for scope changes. Avoid paying for an undefined promise of a finished app. A quote should explain what users can do at each delivery stage, who validates it and how defects are handled. Keep code and project accounts accessible throughout the engagement.