Let me be blunt up front. There is no famous app that magically finds fee waivers for you. The app stores are full of tools with big promises and thin databases. What actually exists are general waiver finders and fee databases, and the quality gap between them is enormous. Five things to compare before you trust one.
First, the database. An application fee waiver finder app for iOS or Android is only as good as its data. How many schools does it cover, and when was it last updated? Waiver policies change every admissions cycle. An app showing last year's rules is not just useless. It is misleading. That is worse.
Second, international coverage. A lot of waiver tools are built around US domestic students. If you are applying from abroad, check whether the app even mentions application fee waiver eligibility for international students. A tool that ignores your situation is not a tool for you.
Third, depth. Some apps list which schools waive fees. Better ones explain how to claim the waiver: who to email, what to say, the deadlines. The "how to get an application fee waiver" part matters more than the list. A list without instructions is a map without roads.
Fourth, the business model. Free apps monetize somehow. If the app funnels you toward paid counseling or sells your data, you should know that going in. A free tool is fine. A free tool with a hidden agenda is not.
Fifth, primary sources. The best finder still requires you to verify on the university's own page. Any app that discourages that is a red flag wearing a friendly icon.
My honest take? For most students, the application fee waiver database at applicationexperts.fyi plus one well-written email to admissions beats any app. Use finders as a starting point, never as a verdict.
Start with the database at applicationexperts.fyi. And if you want the whole two-year plan, not just the waivers, get a 1-2 year profile roadmap.