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Free tool
The “Value this page” bookmarklet shows you the resale price range and an authenticity signal for whatever item you’re looking at — without leaving the page or installing an extension.
Drag this button to your bookmarks bar:
💰 Value this pagehttps://thebackcatalog.com/value?src=bookmarklet&url=https%3A%2F%2Fwww.ebay.com%2Fitm%2F123456&title=Nike+Dunk+Low+PandaThe bookmarklet only reads the page’s title and URL to look up pricing. It doesn’t load any script or change the page.
New to bookmarklets? Read the step-by-step guide.
An instant price range
See the resale low, high, and typical price for the item — pulled from real listings across the marketplaces we track.
An authenticity signal
Know how much the selling platform's provenance is worth, and whether authenticated copies command a premium — clearly labelled, never a guess about the item itself.
No install, no tracking
It's a single bookmark, not an extension. It reads only the page title and URL to look up pricing — it loads no script and never changes the page.
Add the button once
Drag “Value this page” to your bookmarks bar. That's the whole install.
Open any listing
Browsing eBay, Grailed, StockX or anywhere else? Stay on the listing you're curious about.
Click the bookmark
A new tab opens with the item's resale price range and authenticity signal — in about a second.
The bookmarklet works on any product page. On these sites it can also show a platform authenticity signal:
Prefer to paste a link?
You don’t need the bookmarklet to get a valuation. Drop any marketplace URL — or just an item name — into the valuation tool.
Open the valuation tool