CardShark

Underpriced cards, flagged instantly!

Pokémon card, the kind of card CardShark tracks live market pricing for -32%
-24%
-17%
+9%
≈ market

CardShark checks every eBay Magic The Gathering, Pokémon, and Yu-Gi-Oh! listing against real market prices while you browse. Green badge, good deal!

Add to Chrome Free · installs in seconds
No sign-up No paywalls Every setting unlocked
See it in action

Three screenshots. That's the whole product!

A CardShark badge on an eBay listing detail page showing the market price and percent below market
On the listingMarket price and exact savings, next to eBay's price.
CardShark's deal summary panel listing multiple underpriced cards found on a search results page
Deal summaryEvery underpriced listing on the page, in one panel. No scrolling!
CardShark's settings popup showing toggles for Magic, Pokémon, and Yu-Gi-Oh! with a deal threshold slider
Your settings, unlockedEvery toggle, every price source. Free for everyone!
Why CardShark

What it actually does.

Not a flip tool. Not a bot. An honest price check, right where you're already shopping.

Real-time market pricing

Live prices from Scryfall, pokemontcg.io, and YGOPRODeck, the same data serious collectors already trust.

Condition-aware comparisons

Reads NM/LP/MP/HP/damaged straight from the listing title and adjusts the price to match. Apples to apples.

Exact-print matching

Matches foil, treatment, set code, and language, not just the card name. The price you see is the price of that print.

Deal summary panel

One panel lists every underpriced listing on the page. No scrolling, no squinting.

Fully customizable

Pick your price source per game. Set your own deal threshold. Factor in shipping. Nothing's locked.

Nothing leaves your browser

No accounts, no backend, no tracking. Settings stay on your device. See the privacy policy.

How it works

Three steps. Zero setup!

1

Browse eBay like normal

Search Magic, Pokémon, or Yu-Gi-Oh! on eBay.com, eBay.ca, or eBay.co.uk.

2

CardShark reads the listing

It matches the title to the exact card and print, then pulls the current market price.

3

Spot the deal instantly

A badge shows up next to the price. Green means good!

Free. Actually free!

No trial. No tier. No "upgrade to unlock." CardShark runs entirely in your browser against free public price APIs. There's no backend to paywall in the first place.

  • No account or email required
  • No page limits
  • Every setting unlocked
  • No ads
Add CardShark to Chrome
FAQ

Good questions!

Is CardShark really free, no catch?

Yes. No license key, no account, no page limit, no locked settings. It's a client-side browser extension that calls free public price APIs. There's no backend to charge for.

Which card games does it support?

Magic: The Gathering, Pokémon, and Yu-Gi-Oh!, using Scryfall, pokemontcg.io, and YGOPRODeck respectively. Toggle each one on or off independently.

Which eBay sites does it work on?

eBay.com, eBay.ca, and eBay.co.uk. Search results pages and individual listing pages, both.

Does CardShark support graded slabs (PSA, BGS, CGC)?

Not yet. CardShark flags graded listings instead of showing a misleading raw-card comparison. Slab-specific pricing is planned for a future version.

What data does CardShark collect?

None. Settings are stored locally in your browser. See the full privacy policy for details on the (public, non-personal) API calls the extension makes.

Is CardShark affiliated with eBay, Wizards of the Coast, The Pokémon Company, or Konami?

No. CardShark is an independent, unofficial tool. Card names and trademarks belong to their respective owners.