Amazon FBA is a powerful tool for scaling your e-commerce business—but it’s also riddled with pitfalls that can eat into your profits. From rejected shipments to hidden fees, even small FBA prep mistakes can cost you time, money and valuable sales opportunities. In fact, 1 in 5 Amazon sellers report losing 10–20% of their monthly revenue due to FBA compliance issues.

As experts who’ve helped Amazon sellers eliminate rejected shipments and scale sales 3x, we’re breaking down the 5 most costly FBA prep mistakes—and sharing proven strategies to avoid them.

1. Ignoring Amazon’s FNSKU Labeling Requirements

Amazon’s FNSKU (Fulfillment Network Stock Keeping Unit) is a unique barcode that identifies your products in Amazon’s fulfillment centers. One of the most common mistakes sellers make is using incorrect or poorly printed FNSKUs:

Using manufacturer barcodes instead of FNSKUs (which can lead to inventory mixing)
Printing barcodes that are too small, blurry, or placed on curved surfaces (unscannable)
Missing barcodes on individual units or outer boxes

The result? Amazon rejects your shipment and you’re stuck paying re-prep fees (often $0.50–$2 per unit) and losing sales while your inventory sits in limbo.

Solution: Work with an FBA prep partner that has dedicated specialists trained on Amazon’s latest labeling rules. Every unit should undergo a double inspection to ensure FNSKUs are correctly printed, placed and scannable.

2. Improper Packaging for Fragile Items

Fragile products (e.g., glassware, electronics, home goods) require Amazon-compliant packaging to prevent damage during transit. Sellers often cut corners here by using thin bubble wrap, inadequate padding, or non-corrugated boxes—leading to damaged inventory, negative reviews and Amazon penalties.

Solution: Invest in custom packaging designed for your products. For example, use corrugated inserts for small storage solutions, bubble wrap for fragile components and clearly label boxes with “Fragile” or “Handle With Care.” A good FBA prep partner will design packaging that meets Amazon’s standards while protecting your products.

3. Underestimating Prep Time (Leading to Stockouts During Peak Seasons)

Amazon’s fulfillment centers (FCs) can take 2–3 weeks to check in inventory during peak periods (Prime Day, Black Friday, holiday season). If you wait until the last minute to prep and ship your products, you’ll miss out on sales when demand is highest.

Solution: Partner with a prep provider that offers 48-hour turnaround times for FBA prep. Consolidate shipments to Amazon FCs via dedicated carrier partnerships to reduce check-in time to 1–3 days. This ensures your bestsellers are always in stock, even during peak demand.

4. Paying Amazon’s Hidden Placement Fees

Amazon charges placement fees when your inventory is stored in multiple FCs or requires additional handling (e.g., oversized items, mixed shipments). Many sellers don’t realize these fees add up—costing $1,000–$3,000 per month for mid-sized brands.

Solution: Work with a prep partner that offers consolidated shipping to Amazon FCs. By shipping all your inventory to a single FC (or a small number of FCs) via dedicated carriers, you can eliminate placement fees entirely.

5. Failing to Stay Updated on Amazon’s Policy Changes

Amazon’s FBA policies are constantly evolving—from packaging requirements to product safety standards. If you’re not staying informed, you risk non-compliance, rejected shipments and even account suspension.

Solution: Partner with an FBA prep provider that has a team dedicated to monitoring Amazon’s policy changes. They should update their prep processes proactively and provide monthly updates to keep you in the loop. This takes the burden off your team and ensures long-term compliance.

Real-World Result: HomeGear Eliminates FBA Rejections & Scales 3x

HomeGear, a mid-sized Amazon seller specializing in home storage solutions, was struggling with 18% of FBA shipments rejected, 2-week inventory check-in times and $2,000/month in placement fees. After switching to CLUMN’s FBA Prep service:

They achieved 0% rejected shipments (100% compliance)
Inventory check-in time dropped from 2 weeks to 1–3 days
They saved $3,500/month in placement fees and labor costs
Monthly sales grew from 1,200 to 3,600 orders

“CLUMN’s team knows Amazon’s policies inside out,” said Ryan Patel, HomeGear’s owner. “We never miss a sales opportunity now, especially during Prime Day and Black Friday.”

Avoid FBA Mistakes—Grow Your Amazon Business

FBA prep doesn’t have to be a headache. By avoiding these 5 costly mistakes, partnering with a knowledgeable prep provider and staying proactive about compliance, you can reduce costs, eliminate stockouts and scale your Amazon sales.

Whether you’re a new seller or an established brand, the right FBA prep strategy can turn logistics from a cost center into a revenue driver.