Cardillions watches the major marketplaces and auction houses around the clock, computes the true landed cost of every listing — hammer price, buyer's premium, tax, shipping — and alerts you the moment a card is available under its Card Ladder value, or a player starts moving before the weekly update catches up.
Card Ladder is the number the hobby negotiates against — but it updates on roughly a one-week lag, and nobody can watch five auction feeds at once. Software can.
A sale takes about a week to show up on Card Ladder and become the new "value." Everything that happens inside that window is edge.
Most sellers take ~85% of Card Ladder for cash in person. An online deal only matters if the landed cost beats that floor.
A $1,000 hammer at Goldin actually costs $1,220. Sticker price is a lie — only landed cost tells you if a listing is under value.
Every live listing and closing auction is matched to its exact card and grade, priced all-in, and compared to the last several Card Ladder sales.
Card Ladder value $1,000 (average of the last 5 sales). Trade-show cash price ≈ $850.
| Where | Hammer | Premium | Landed cost | Verdict |
|---|---|---|---|---|
| Goldin auction | $700 | 22% | $854 | Marginal — even with a trade show |
| Alt auction | $650 | 20%, no tax | $780 | 22% under value — alert |
The core math, live. Pick a platform (buyer's premium fills in automatically), enter the price and the Card Ladder value, and see whether it's actually a deal.
Under 75% → act now · under 85% → deal (beats the trade-show floor) · 85–100% → marginal · over 100% → above market.
Whatnot runs enormous volume in live-stream auctions, and none of those sales feed into Card Ladder. Cards regularly hammer below the reference number because the buyer pool in a single stream is thin — and the sale never drags the value down afterward. It's the biggest untracked pool of mispriced cards in the hobby, and it's on the Cardillions roadmap.
What the buyer actually pays on top of the hammer — the column that decides whether a listing is really under value.
| Platform | Buyer pays | Notes |
|---|---|---|
| eBay | 0% | Largest volume by far. Official Browse API for live listings. |
| Alt | 20% (auctions) | Graded cards only, Delaware vault — no sales tax. 0% on fixed price. |
| Fanatics Collect | 22% | Weekly + premier auctions, vault, Sotheby's partnership on grails. |
| Goldin | 22% | $19 minimum premium. Premium sports, TCG, and pop culture. |
| Whatnot | 0% | Live-stream auctions. Not indexed by Card Ladder — the blind spot. |
| Heritage | 20% | Vintage and six-figure cards; premium applies up to $500k. |
| MySlabs | 0% | Lowest-fee graded marketplace — peer-to-peer mispricing lives here. |
| REA · Lelands · Mile High · SCP | ~20% | Vintage-focused houses with overlapping calendars; public archives. |
Fee schedules change frequently; numbers are verified against each platform before the engine relies on them.
Start narrow, prove the matching and the math, then widen.