Where Card Prices Actually Come From

Look up one card in three places and you'll get three prices. None of them is lying — they measure different things.

Sales vs. asks

A sale is what someone actually paid. An ask is what a seller hopes to get. Marketplace "market prices" are models built mostly from recent sales — but when a card stops selling, some sources quietly carry the last computed value or drift toward listing prices. That's how a card nobody would pay $500 for can display $500 for months.

The frozen-price test

The single most useful check: has the price moved lately? A sales-backed price wiggles, because real sales never repeat to the penny. A price frozen for weeks is usually an ask in disguise. CardStock runs this test nightly on every card, in both directions — a frozen price sitting far above fresh sales elsewhere is a stale listing, and one sitting far below is usually a dead product page — and switches the card to its sales-backed source when the evidence says so.

Why sources disagree on healthy cards too

Even with real sales everywhere, venues differ: auction sites skew toward impatient sellers and bargain hunters; storefront marketplaces skew toward patient sellers with buyer protection. A persistent 10–30% spread between venues is normal, not an arbitrage machine — fees and shipping eat most of it.

What we do when no source is defensible

Some cards — misprints, tournament prizes, brand-new releases — briefly have no trustworthy price anywhere: the only listing is aspirational and there are no sales. We show nothing rather than something invented, and the card returns when real data does. A blank is information too: it means nobody actually knows.