Underpriced slab: the real margin before you buy
A PSA, CGC or BGS slab listed below recent sales of the same card in the same grade is a flip, as long as the margin holds after selling fees and shipping. Work it out before you buy.
Result
How to spot an underpriced slab
Always compare the listing to the median of completed sales for the same card, in the same grade, from the same grader, never to other active listings. Watch out for the usual traps:
- a different version of the card (edition, holo variant, language, number);
- an in-house grade or a non-official case;
- too few sales for the median to mean anything;
- a cracked case or a label that doesn't match the photos.
What the Filons tab does for you
The Filons tab goes through the eBay listings from your searches, compares every slab with the median of comparable sales, works out the resale margin after fees and ranks listings from most to least profitable. For each card, it also checks two other strategies: buying the raw card to grade it, or starting from another grader.
Let Kardz find underpriced slabs
The Filons tab compares every listing with real sales of the same card and grade, then works out the margin after fees.
Open the Filons tab Free account, no credit card · full margin details with the 7-day trialFAQ
What is a slab?
A card graded by a grading company (PSA, CGC, BGS, SGC…) and sealed in a hard case with a label showing the grade and a certification number.
Why the median rather than the average?
A single outlier sale (a lot, a miscategorized item, a runaway auction) is enough to skew an average. The median, the middle value, holds up against those extremes.
How many sales do I need to trust the price?
The more the better. With one or two sales, the reference price is fragile: spend less or ask for a wider margin.
What margin should I aim for?
Set your own threshold, allowing for time to resell and surprises. For reference, Kardz's deal of the day never picks an opportunity below 15%.
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Page updated September 24, 2026 · Kardz is not affiliated with PSA, CGC or eBay. Results are estimates, not financial advice.