Amazon Pricing Strategy: Buy Box Algorithm, Repricing Tools & Floor Rules

The Buy Box is the "Add to Cart" button on a product detail page. Approximately 82% of Amazon sales go through the Buy Box — not through the "Other Sellers" listing. Winning the Buy Box is not simply about having the lowest price; it is about having the best combination of price, fulfillment quality, and seller performance metrics.

Amazon's Buy Box algorithm weights: landed price (item price + shipping), fulfillment method (FBA > SFP > FBM), seller feedback rating (target >95%), Order Defect Rate (<1%), late shipment rate (<4%), valid tracking rate (>95%), and response time (under 24 hours for FBM).

For brand sellers with Brand Registry who are the only seller on their ASIN, the Buy Box is effectively guaranteed as long as performance metrics are healthy and your account is in good standing. The repricing game is most relevant for resellers competing on the same ASIN.

Even as a private label brand, if you allow resellers or distributors to sell on your ASIN, they compete for the Buy Box with you. Controlling your distribution (enforcing MAP policy, issuing limited reseller authorizations) protects your Buy Box ownership.

MAP (Minimum Advertised Price) is a policy you set for any authorized US resellers or distributors. Resellers agree not to advertise your product below your MAP. While MAP does not legally prevent resellers from selling below MAP (US antitrust law distinguishes between price floor policies and resale price maintenance), it gives you a contractual basis to terminate unauthorized resellers.

Amazon does not enforce MAP — they have no contractual relationship with your MAP policy. But you can report MAP violators to Amazon and request their listings be removed if they are selling counterfeit or unauthorized product.

For Taiwan brands selling directly on Amazon as the brand owner, MAP is most relevant when you also have B2B distributors whose customers may set up Amazon seller accounts. Enroll with Amazon's Brand Registry and use Project Zero + IP Alert to monitor and remove unauthorized sellers.

Repricers monitor your Amazon listing price and competitor prices in real time and adjust your price automatically within your defined floor and ceiling bounds. They are designed to win or maintain the Buy Box while maximizing revenue.

Rule-based repricers (e.g., Repricer.com, BQool): set a rule like "price $0.01 below the lowest competitor." Simple and cheap ($50–150/month) but race to the bottom in competitive categories.

AI-based repricers (e.g., Seller Snap, Feedvisor): use machine learning to predict optimal price points that win the Buy Box without unnecessarily dropping price. They model competitor behavior patterns and time price changes strategically. More expensive ($200–1,000+/month) but generate higher revenue per unit in head-to-head tests.

For Taiwan private label brands who own their ASIN exclusively: a repricer is less critical since you automatically win the Buy Box. A repricer becomes valuable when you test multiple price points for conversion rate optimization — set it to slowly test prices between your floor and ceiling and track unit session percentage changes.

Floor price: the minimum price at which you will never sell, regardless of competitive pressure. Calculate it from your landed cost model: Floor = Landed Cost + FBA Fee + Amazon Referral Fee + Minimum Acceptable Net Margin (e.g., 10%). Never set a floor below break-even.

Ceiling price: the maximum price you are willing to charge. Set it based on competitive market research — the highest price in your category where you can still win the Buy Box organically or maintain acceptable conversion rates.

Update your floor price every time your landed cost changes (freight rate adjustment, FBA fee schedule change, new duty rate). A repricer that never has its floor updated will eventually price you below profitability during a competitive price war.

Most sellers only reprice downward. The smarter strategy is velocity-based pricing: when a product is selling faster than expected (high conversion rate, limited stock), raise the price — you can often capture more revenue per unit without significantly hurting volume.

Indicators to raise price: conversion rate >20% at current price, Best Seller Rank climbing while Buy Box held, inventory level dropping below 30-day supply. In these scenarios, a $1–2 price increase often maintains conversion while improving margin.

Post-Prime Day price recovery: after a promotional event, restore pricing to normal or slightly above normal within 48 hours. The post-promotion period often has elevated residual traffic — leaving promotional pricing in place during this window gives away margin unnecessarily.