Comping is a browser extension for resellers doing online arbitrage. It shows eBay sold prices and an estimated profit margin for whatever you're looking at, so you can tell in seconds whether an item is worth flipping.
Comping recognizes product pages automatically as you browse, including Amazon — no need to search eBay yourself.
Click the small badge that appears to see the eBay sold-price median, range, and a profit estimate compared to the page's price — after eBay's fees and shipping.
No product data on the page? Highlight any text, right-click, and choose "Check eBay sold prices" — or use the toolbar search box.
Automatically compares against the right regional eBay marketplace, so the profit math never mixes currencies.
Stays out of the way on search results, carts, and checkout pages — only shows up on real product pages. Per-site opt-out if you don't want it on a given store.
Everything Comping stores lives only in your own browser. Read the full privacy policy.
A plain eBay search mixes in accessories, damaged or "for parts" listings, counterfeits, multi-item lots, and different variants of the same product. Comping filters all of that out first, based on a systematic audit of 1,000 real products. Read how the accuracy work was done.