Alt art vs overnumbered vs signature
The vocabulary that decides the price. What an alt art, an overnumbered and a signature printing each are, how to tell them apart on the card, and which is rarest.
Two listings, same card name, one is four dollars and the other is four hundred. The difference is the printing, and the vocabulary for it is small enough to learn in five minutes. It is the single most valuable thing a new collector can know.
The four you will meet

Alt art
Different artwork on an otherwise identical card. The most common of the special printings, and the widest range in price. Some are barely above base, some are genuine chase cards.
Spotting it: Look for a different illustration to the standard version, usually with the card name marked as an alternate art.
Dearest in the catalog: Teemo - Swift Scout (Alternate Art) at $450.12.

Overnumbered
A collector number above the set's normal card count. That number is the tell: if a set runs to 300 cards and the number reads higher, it is an overnumbered printing.
Spotting it: Check the collector number against the set size. Nothing else about the card need look unusual.
Dearest in the catalog: Ahri - Inquisitive (Overnumbered) at $650.42.

Signature
The rarest tier, carrying a signature treatment. Typically the most expensive version of any card that has one, by a wide margin.
Spotting it: Marked on the card and in the name. If a card exists as a signature, that is almost certainly the priciest printing of it.
Dearest in the catalog: Ahri - Inquisitive (Signature) at $6,806.94.

Metal
A physically different product rather than a rarity tier. Notably, these often trade below the ordinary card rather than above it.
Spotting it: Named as such. Do not assume a premium. Check the price against the base printing first.
Dearest in the catalog: Ahri - Nine-Tailed Fox (Metal) at $146.29.
Base printings
Everything else is a base printing. That is the ordinary version, and the one you want if you are building a deck or completing a set on a budget. Base cards are cheap in every set, including the expensive ones.
How to not overpay
- Check the collector number first. It is the card's unambiguous address, and it distinguishes printings that share a name.
- Compare like with like. A base printing being cheaper than a signature is not a bargain, it is a different card.
- Use the printings table. Every card page here lists all printings side by side with prices, so the spread is visible before you buy.
- Do not assume special means expensive. Metal printings are the standing counterexample.
Common questions
What is the difference between alt art, overnumbered and signature printings?
Alt art is the same card with different artwork, overnumbered sits above the set's numbering, and signature carries an artist signature and is the rarest of the three. The order matters because it is also the price order.

