Marketplace

## Architecture Role-based guidance for marketplace participation. Load relevant file based on user's role. ``` marketplace/ ├── buyer.md # Price comparison, scam detection, negotiation ├── seller.md # Listing creation, pricing, platform rules ├── builder.md # Marketplace creation, economics, liquidity ├── arbitrage.md # Price gaps, ROI calculations, ToS risks └── compliance.md # Tax obligations, legal pitfalls, bans ``` ## Quick Reference | Role | File | When to Load | |------|------|--------------| | Buying items | `buyer.md` | Comparing prices, spotting scams, negotiating | | Selling items | `seller.md` | Creating listings, pricing, handling buyers | | Building marketplace | `builder.md` | Designing platform, economics, payments | | Arbitrage/Reselling | `arbitrage.md` | Finding price gaps, calculating true ROI | | Legal/Tax questions | `compliance.md` | Tax nexus, ToS violations, suspensions | ## Core Rules ### 1. Platform-Specific, Never Generic - Each platform has unique fees, rules, and dynamics - eBay auction ≠ Amazon Buy Box ≠ FB Marketplace negotiation - ALWAYS specify which platform advice applies to ### 2. Total Cost, Not Sticker Price - Include: platform fees, shipping, taxes, return costs - Amazon referral fee varies 8-45% by category - eBay 13%+ Poshmark 20%+ Mercari varies ### 3. Scam Pattern Recognition - Stock photos on local marketplaces = red flag - "Ship to my address, I'll pay extra" = triangulation fraud - Payment outside platform = no protection - New account + high-value item + urgency = likely scam ### 4. Pricing Research = SOLD, Not Listed - Listed prices mean nothing—items don't sell at listed price - Always research completed/sold listings - Factor in condition: "Good" vs "Very Good" = 30% price difference ### 5. Suspension Risks Are Real - Amazon ODR >1% = account death - Review manipulation = permanent ban - IP complaints from brands = immediate suspension - Multiple accounts = instant termination ### 6. Fee Complexity Never estimate fees—calculate exactly: - Amazon: referral + FBA + storage + return processing + advertising - eBay: final value (category-specific) + promoted listings + payment - Factor returns into margin (15-30% in some categories) ### 7. Real-Time Data Required - Never quote prices from memory/training data - Inventory and pricing change hourly - Competitor stock levels affect optimal pricing - Always verify current marketplace state before advising