A lot of Amazon profit is won or lost before a product reaches the warehouse. I've been sourcing products since 2013, and most of the expensive mistakes I've seen, my own included, fall into the same few categories.
1. Not checking the supplier properly
A good website and fast replies aren't proof of a reliable factory. Before placing a real order:
- Ask for business licenses and, ideally, a third-party factory audit.
- Check whether you're dealing with the factory or a trading company. Both can work, but you should know which.
- Start with a smaller first order, even if the unit price is higher.
2. Skipping quality control
Samples are often made with more care than production runs. Book a pre-shipment inspection for every order, with a clear checklist: dimensions, materials, function, packaging and labeling. On Amazon, a bad batch shows up as returns and one-star reviews, and those hurt rank long after the stock has gone.
3. Vague specifications
"Same as the sample" isn't a specification. Put the details in writing: materials, colors (with Pantone references), tolerances, packaging, carton size and labeling. Confirm them in the purchase order, so there's no argument if something is wrong.
4. Not negotiating the right things
Price per unit isn't the only lever. Negotiate:
- MOQs, especially for new products or new colors
- Payment terms, for example 30% deposit and 70% after inspection
- Packaging that fits Amazon's requirements and keeps you in the cheapest FBA size tier
5. Ignoring the landed cost
The real cost of a product is the landed cost: unit price plus freight, duties and tariffs, inspection, prep, labeling and inbound fees to Amazon. With US tariffs changing frequently, recalculate landed cost for every order rather than reusing last year's figure.
6. Freight and labeling problems
Delays and refused shipments usually come from paperwork and labels: wrong carton labels, missing FNSKU barcodes, or shipments that don't match the plan in Seller Central. Since March 2026 Amazon no longer accepts new stickerless, commingled inventory, so check your barcode settings before every shipment. Our barcodes guide explains the options.
7. Poor inventory planning
Order too little and you stock out, lose rank and pay low-inventory fees. Order too much and you pay storage and aged inventory surcharges. A simple plan prevents both:
Reorder point = daily sales × (production time + shipping time + receiving time) + safety stock
Use your recent sales velocity, not a hopeful forecast, and add extra buffer before Q4 and Prime Day.
Best and worst practices at a glance
| Area | Best practice | Common mistake | Impact on Amazon |
|---|---|---|---|
| Supplier checks | Audit and verify | Trusting without proof | Scams, bad batches |
| Quality | Pre-shipment inspection | No inspection | Returns, bad reviews |
| Specs | Written, detailed | "Same as sample" | Disputes, inconsistent product |
| Costs | Full landed cost | Unit price only | Lower margin than expected |
| Logistics | Reliable forwarder, correct labels | Wrong paperwork | Delays, refused shipments |
| Planning | Velocity-based reorder points | Guesswork | Stockouts or storage fees |
The bottom line
Good sourcing is mostly discipline: verify, inspect, specify, cost everything and plan with real data. The products that make the most money on Amazon are rarely the ones with the cheapest unit price.
Our inventory management service handles the planning side, with weekly stock reports and reorder recommendations based on your actual sales velocity and lead times.