I built a free iOS app for my wife's car boot sale business in 31 days

My wife buys secondhand items at car boot sales and flea markets in the UK, then resells them on eBay, Vinted, and Facebook Marketplace. She was tracking everything in Google Sheets — purchase prices, listing dates, what sold where, entry fees, petrol costs. It was a mess.

She looked at existing apps but didn't want to pay £10/month for something that might not even work offline at a field in the middle of nowhere. So she asked me to build something.

The build

I started on February 20, 2025. Swift, SwiftUI, no backend. The core idea was simple: snap a photo at the market, log the price, track where you list it, record the sale, and see your real profit after ALL costs.

• Day 1 — First working version. Photo capture, price logging, save to JSON

• Day 7 — Multi-currency support (she buys in GBP, sometimes sells in EUR/USD) with automatic exchange rates

• Day 14 — Expense tracking, Money Flow analytics dashboard, listing reminders

• Day 18 — Migrated from JSON to SQLite because performance was getting bad with hundreds of items

• Day 23 — Full Figma redesign, every screen rebuilt from a proper design system

• Day 31 — Live on the App Store
  

I used Claude Code for AI-assisted development throughout, which made the solo timeline possible.

What it does

• Track items with photos from purchase → listing → sale

• 16 selling platforms (eBay, Vinted, Facebook, Depop, Poshmark, etc.)

• Real profit calculation after entry fees, transport (car, bus, train, taxi), and other expenses

• 4 currencies with automatic daily exchange rates

• Works completely offline — syncs to Google Drive when you're back online

• Generates unique SKUs for each item you can use in your listings

The Reddit moment I posted about it on r/FlippingUK and r/Flipping while it was still on TestFlight. People actually wanted to use it. They asked how to get it. That's what pushed me to publish it on the App Store instead of keeping it as a personal tool. It's completely free. No ads, no subscriptions, no premium tier yet. I wanted to keep running costs at zero — no backend, no server, everything runs on-device with optional Google Drive sync. My only cost is the Apple Developer account.

If people find it useful, I might add paid features later. For now I'm focused on making the free version genuinely good.

Links

• App Store: https://apps.apple.com/us/app/flipperhelper/id6759716745

• Website: https://flipperhelper.app/

• Subreddit: https://www.reddit.com/r/flipperhelper/

Happy to answer any questions about the build, the tech decisions, or the car boot sale flipping world.