Budget E-Commerce Mobile App

I’m looking for a lean, no-frills e-commerce application that runs smoothly on both iOS and Android while keeping the total build cost below $30. The core aim is to let customers browse items, add them to a cart, and check out through a simple, intuitive interface.

Key expectations
• Cross-platform build: the same codebase should compile cleanly for iOS and Android.
• Essential store flow: product listing, search or filter, cart, and checkout with at least one working payment gateway or a dummy checkout for now.
• Lightweight assets: the app must install quickly and perform well on entry-level devices.
• Ownership of source: I need full source files plus ready-to-install binaries (APK and IPA/TestFlight build).
• Clean hand-off: include a short read-me on how to rebuild and change basic store data (names, prices, images).

I’m happy to supply the product catalogue once development starts, and I can handle publishing if you guide me through any platform-specific steps.

Because the budget ceiling is tight, I’m open to templates, open-source starters, or rapid-build tools so long as licensing stays commercial-friendly. When you reply, show me one or two small apps you’ve built on a shoestring and explain briefly how you’d keep costs inside the limit.