Margin Seller: Profit, Margin & Buy Signal for Amazon and Walmart Sellers

Margin Seller: Amazon™ & Walmart™ Profit & Margin Calculator & Buy Signal Supports the USA and Canada marketplaces TURN ANY PRODUCT PAGE INTO A BUY DECISION Before you spend money on inventory, know whether the numbers work. Margin Seller is a Chrome extension profit calculator and buy signal tool for Amazon and Walmart sellers. Open a product page, enter your supplier cost, and see estimated profit, margin, ROI, break-even price, and a clear Buy, Review, or Avoid recommendation in seconds. Margin Seller uses the product information visible in your active browser tab. It does not require an Amazon or Walmart API, Seller Central login, marketplace credentials, or background scraping. Open any supported Amazon or Walmart product page, click the extension, and immediately analyze the listing details visible in your active tab. Combine real-time marketplace data with your supplier cost and operating assumptions to calculate your exact bottom line. KEY FEATURES • Real-Time Profit Checker: Estimate net profit per unit, net margin, and ROI instantly for both Amazon FBA/FBM and Walmart WFS listings. • Risk & Pricing Guardrails: Calculate your break-even price, maximum buy price, and get clear Buy, Review, or Avoid recommendations. • Custom Operating Assumptions: Factor in referral fees, fulfillment (FBA / WFS), advertising, shipping, discounts, and return rates. • Reverse Sourcing: Input a target ROI to reverse-calculate your maximum supplier purchase price. • PPC Campaign Modeling: Model profitability across ACOS and TACOS campaign scenarios. • Local Research & CSV Export: Save local research history and export clean CSV reports for your catalog audit. • Browser-Assisted Batch Research (Pro): Upload a supplier CSV containing cost plus an ASIN or Walmart ID. Margin Seller generates safe product links and queues rows for manual, visible-page reading. HOW IT WORKS Open a product listing on Amazon.com or Walmart.com. Click the Margin Seller icon to open the side panel. Review the listing price, category, weight, fulfillment details, and other visible product data. Enter your supplier cost and operating assumptions. Get a margin calculation and buy signal before committing to inventory. SEE THE NUMBERS THAT MATTER • Estimated net profit per unit • Net profit margin and return on investment (ROI) • Break-even selling price • Maximum buy price for your target ROI • Buy, Review, or Avoid signal with a plain-English explanation • Amazon FBA, FBM, and Walmart WFS fulfillment estimates • Category-based referral fee estimates • Price-drop scenarios for 5%, 10%, and 15% downside • Seller-fulfilled cost comparisons The result is a practical sourcing estimate based on the listing data and assumptions you provide. Use it to compare products, screen opportunities, and decide which items deserve a closer look. MODEL YOUR REAL OPERATING COSTS Adjust the assumptions that affect your actual margin: • Supplier cost per unit • Inbound shipping to your warehouse • Fulfillment method and fulfillment costs • Advertising spend per unit • ACOS and TACOS scenarios for PPC planning • Return rate and discount rate • Target ROI for reverse sourcing Reverse sourcing works backward from your target ROI to show the maximum supplier price you can pay. BUILT FOR AMAZON AND WALMART SELLERS Amazon sellers can evaluate FBA and FBM opportunities across standard product categories and size tiers. Walmart sellers can evaluate Walmart Fulfillment Services (WFS) and seller-fulfilled listings. The extension is useful for online arbitrage, retail arbitrage, wholesale, private label, and general ecommerce sourcing. KEEP YOUR RESEARCH ORGANIZED • Save product research locally for later comparison • Export saved audits as clean CSV reports • Review listing price snapshots across repeat visits • Check supplier pack size against the marketplace listing pack • Use the web app for deeper audit review and planning PRO BATCH RESEARCH Pro users can upload a supplier CSV containing supplier costs, ASINs, or Walmart Item IDs. Margin Seller creates product links and queues each row for manual, visible-page review. Results can then be combined into a local catalog audit. Batch research is browser-assisted, not automated crawling. The extension does not scan marketplace pages in the background. FREE TO START Margin Seller is free to install, and you can start calculating without an account. Free — 5 calculations per month with local margin analysis. Seller — $29/month with 500 scans per month, saved audits, CSV export, price tracking, and web app sync. Pro — $79/month with unlimited scans, PPC and ACOS/TACOS scenario modeling, cost profiles, and batch catalog audits. Upgrade directly from the extension side panel. PRIVATE, TRANSPARENT, AND COMPLIANT Margin Seller reads only product details already visible in your active browser tab. It does not access Seller Central, Walmart Seller Center, marketplace account pages, payment information, or private seller data. It does not crawl pages in the background and does not include third-party analytics or browsing tracking. Your product research and calculations stay in your browser. Nothing is uploaded without your explicit action. Margin Seller does not require an Amazon or Walmart login and is not affiliated with, endorsed by, or sponsored by Amazon™ or Walmart™.