School Art Marketplace App

I’m building a cross-platform (iOS and Android) multi-vendor marketplace focused on school art, stationery, printed goods, and digital designs. The app must allow a teacher or parent to post a request-for-quote, compare several vendor offers, split the payment 50 / 50, and pick a preferred delivery option, all while vendors manage their own catalogue and order flow.

Core scope
• Three user roles need full lifecycle management inside the app: Vendors, Customers, and Admin.
• Vendor tools must cover Product listings, Order management, and detailed Sales reports.
• Partial-payment checkout supports Credit/Debit Card and Apple Pay.
• Dashboards for both vendor and admin views showing sales, order status, and RFQ conversions.
• Real-time push notifications, in-app messaging, ratings & reviews, and multiple delivery methods (pickup, courier, digital download for design files).

Deliverables
1. Native or cross-platform mobile apps compiled for App Store and Google Play.
2. Cloud-hosted backend with REST / GraphQL APIs, secure authentication, and role-based access.
3. Web-based admin panel that mirrors the mobile dashboards.
4. Source code, build scripts, and basic deployment documentation.

Please outline your proposed tech stack, estimated timeline (milestones are fine), and total cost. Indicate any past marketplace projects or multi-vendor apps you have shipped; links or store references help speed up selection.