What a spreadsheet does well
A well-built Google Sheet handles the basics of reselling: one row per item, columns for purchase price, listing date, platform, sale price, fees, profit. Add a SUMIF for monthly totals and you have better records than most casual sellers. Zero cost, total flexibility, your data stays yours.
We even recommend starting there: you learn what you actually need to track before paying for anything.
The four breaking points
1. Data entry stops happening
The spreadsheet doesn't fail technically — it fails behaviorally. Around 50+ items in stock and 30+ sales a month, updating rows after a long sourcing day is the first thing you skip. Three weeks later the sheet is fiction, and rebuilding it from platform statements takes a full weekend.
2. Lot costs break your formulas
You buy a $60 bundle of 15 items. What did each item cost? If you allocate $4 each, what happens when 5 never sell? Cost allocation across lots — the core of thrift/bundle economics — is where spreadsheet formulas turn into spaghetti. (It matters: your real margin depends on it.)
3. Multi-platform fees diverge
Vinted takes 0%, eBay ~13.25% + $0.30 including on shipping, Poshmark 20%. One "fees" column can't model that, so people hardcode per-row values, mistype them, and quietly corrupt their profit numbers.
4. Tax season
A 1099-K (US) or DAC7 report (EU) states your gross sales. Your defense against overpaying tax is per-item cost records. A half-maintained spreadsheet is exactly the evidence you don't want to bring.
Spreadsheet vs. app, feature by feature
| Spreadsheet | Reseller app | |
|---|---|---|
| Cost | Free | Free tier → ~$5–15/mo |
| Entry speed | Slow, desktop-bound | Seconds, from your phone at the thrift store |
| Lot / bundle costs | Manual formulas, fragile | Built-in allocation |
| Per-platform fees | Hardcoded per row | Applied automatically per marketplace |
| Margin per item / niche | Possible with pivot tables | Default dashboard |
| Photos of items | No | Attached to each item |
| Tax-ready export | DIY | One click |
What to demand from an app
- Item-level tracking — purchase cost, fees, sale price and net margin per item, not just monthly totals.
- Lot support — buy a bundle, split costs across items without a formula.
- Multi-platform — Vinted, eBay, Depop, Poshmark, Facebook Marketplace and local sales in one place.
- Works offline / on mobile — flea markets have no Wi-Fi; that's where your cost data is born.
- Your data exports — CSV out anytime. If you can't leave, don't enter.
The bottom line
Switch when the spreadsheet costs you more than an app would: in unlogged items, mis-typed fees, and Sunday afternoons rebuilding formulas. For most resellers that line sits around 50 items in stock or 30 sales a month. Before that, a disciplined sheet is genuinely fine — and we'd rather you start with any tracking than none.