Profit MateShort, plain definitions of the words you'll meet in your first month of retail arbitrage. Examples use a real product we scanned.
ASIN
Amazon Standard Identification Number: the 10-character code (letters and numbers) of a product page on Amazon, such as B01B1V10KA. The same product can have a different ASIN in different marketplaces.
BSR (Best Sellers Rank)
A number that ranks how well a product sells compared with the others in its category. A lower number means it sells more often. The ice cream counter in our examples had a sales rank of #156 on 4 Nov 2026.
Buy Box
The Add to Cart box on a product page. Several sellers can offer the same product, but only one offer holds the Buy Box at a time, and most sales go through it. Price, fulfilment method and seller performance all influence who gets it.
FBA (Fulfillment by Amazon)
A program where you send your products to Amazon's warehouses and Amazon stores, packs and ships them, and handles customer service and returns, for a fee.
FBM (Fulfilled by Merchant)
Selling on Amazon while you store, pack and ship the orders yourself. You pay no FBA fee but you pay your own shipping to the customer.
ROI (return on investment)
Profit divided by what you paid for the product, as a percentage. Example: $7.43 profit on a $12.99 buy cost is a 57.2% ROI. Many sellers look for at least 30%.
Margin
Profit divided by the sell price, as a percentage. Example: $7.43 profit on a $35.99 sale is a 20.6% margin.
UPC / EAN
The barcodes printed on products. A UPC has 12 digits and is common in the US; an EAN has 13 digits and is common in Europe. A UPC is an EAN with a leading zero. A scanner app reads the barcode to find the matching Amazon listing.
Hazmat
Short for hazardous materials. Amazon classifies some products, such as certain aerosols, flammable liquids or items with lithium batteries, as hazmat and applies extra rules to storing and shipping them with FBA.
Gated category
A category or brand where you need Amazon's approval before you can list products. What is gated can differ between seller accounts and changes over time, so check in Seller Central before you buy stock.
Referral fee
A percentage of the sell price that Amazon keeps on every sale. The percentage is set by category and is 15% for toys. On a $35.99 sale that is $5.40.
FBA fee
The per-unit fee Amazon charges to pick, pack and ship an FBA order. It depends on the product's size and weight. The ice cream counter in our examples has a $9.51 FBA fee.
Keepa
A service that tracks Amazon price, sales rank and offer history over time. Profit Mate uses Keepa for the price, rank and offer history shown for each product.
Retail arbitrage
Buying products in physical stores, often on clearance, and reselling them on Amazon for more than you paid. See the retail arbitrage guide.
Online arbitrage
The same idea as retail arbitrage, but you buy from online stores instead of physical ones. You search by product name or ASIN instead of scanning a barcode.