Amazon sellers face a fundamental choice: let Amazon warehouse and ship your products (FBA), or handle fulfillment yourself through a 3PL (FBM). Most successful sellers eventually use both. Here is how to decide.**What Is FBA?**Fulfilled by Amazon means you send inventory to Amazon's fulfillment centers and they handle storage, picking, packing, shipping, customer service, and returns. Your products are eligible for Prime shipping automatically.FBA works best for: high-velocity, small, lightweight products where monthly storage fees are manageable. If your product sells fast and is small enough to avoid oversized fees, FBA economics are often favorable.**What Is FBM?**Fulfilled by Merchant means you or a 3PL ships orders directly to Amazon customers. You maintain control over your inventory, packaging, and returns process.FBM works best for: large or heavy items where FBA storage fees are punishing, slow-moving inventory that would incur long-term storage charges, and brands who also sell on other channels and need unified inventory management.**The Real Cost Comparison**FBA fees include: fulfillment fees (based on size and weight), monthly storage fees, long-term storage fees after 365 days, removal fees, and return processing fees. For a standard-size item, total FBA fees typically run $3-8 per unit.FBM via a 3PL like 3PLCity includes: pick and pack fees, storage, and shipping. For most standard items, this runs $4-9 per unit including shipping — comparable to FBA but with no long-term storage penalties and full inventory flexibility.**Why Many Sellers Use Both**Running FBA for fast-moving SKUs and FBM for slower or larger items from the same 3PL gives you the best of both worlds. When FBA inventory depletes, FBM automatically takes over to prevent stockouts and Buy Box loss. One inventory pool, two channels, zero gaps.**3PLCity's Amazon Solution**We support both FBA prep (FNSKU labeling, poly-bagging, carton building, shipment plan management) and FBM fulfillment with same-day shipping. Many of our clients run both channels simultaneously from our Gardena facility.