Allocate money by delivery phase
Discovery clarifies the users, goals and constraints. Design makes the journeys testable before code is written. Implementation covers the app, backend and administration tools, while quality assurance and release preparation make the result usable. Ask which deliverables belong to each phase and what information is required before the next phase starts.
Keep a contingency and control changes
Existing systems, data imports or third-party integrations can reveal unexpected work. Keep a contingency instead of committing the entire budget to the initial feature list. Agree how changes are estimated and approved. Compare actual spending with accepted deliveries throughout the project, and adjust priorities before a shortfall becomes urgent.
Fund the product after launch
Allocate an operating budget for infrastructure, support, security maintenance and product improvements. A technically completed app still needs acquisition, onboarding and feedback collection. Identify the outcome that would justify further investment, then fund the next iteration based on evidence rather than the original wish list.