Marketplace Deal Checker

About

Detailed Description
Stop overpaying on Facebook Marketplace.

Marketplace Deal Checker shows you whether every listing is fairly priced by comparing it against real eBay sold data in real time. A small glass badge appears next to each price telling you if it's a great deal, fair price, or overpriced.

HOW IT WORKS As you browse Facebook Marketplace, the extension automatically checks each listing against recent eBay sold prices. Two parallel searches run per item for accuracy, and statistical outlier removal ensures you get reliable fair market values.

FEATURES

Deal scoring: Great Deal, Good Deal, Fair Price, High, or Overpriced
Fair market value shown for every item
Savings or overpay amount calculated instantly
Condition-aware: flags broken, for-parts, or damaged items so you don't get misled
Click any badge to see the eBay sold listings yourself
Adapts to Facebook's light and dark themes
Supports collectibles at any price (trading cards, designer goods, watches, etc.)
Skips vehicles and real estate where eBay comparisons don't apply
No API key required, no account needed, completely free
PRIVACY This extension only activates on Facebook Marketplace pages. It reads listing titles and prices to search eBay for comparable sold items. No personal data is collected, stored, or transmitted to any third party. All processing happens locally in your browser.