Firestore is cheap for tidy apps: our model puts 10,000 users near $4.86 a month.
One screen that re-reads 1,000 documents on every open pushes the same app to about $455 a month.
Supabase suits teams that want SQL, PocketBase and Appwrite suit self-hosting, and MongoDB Atlas suits document-only needs.
Fix expensive queries with pagination and narrower listeners before you migrate.