Cheapest priced copy (Streets of New Capenna Promos): $0.49 at Card Kingdom, near mint, their price list as of .
Evolving Door 
Artifact · Rare · Streets of New Capenna · #144
{1}, {T}, Sacrifice a creature: Count the colors of the sacrificed creature, then search your library for a creature card that's exactly that many colors plus one. Exile that card, then shuffle. You may cast the exiled card. Activate only as a sorcery.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Streets of New Capenna Promos | 144p | Rare | $0.49 | $0.49 |
| Streets of New Capenna Promos | 144s | Rare | — | $0.49 |
| Streets of New Capenna | 144 | Rare | $0.49 | $0.49 |
| Streets of New Capenna | 429 | Rare | $0.49 | $0.49 |
5 rulings from Wizards of the Coast
- 29 April 2022You count the colors of the sacrificed creature as it last existed on the battlefield. Notably, if it was a double-faced card or a copy of another creature, that may be different from what its colors are in the graveyard.
- 29 April 2022If you choose to cast the spell, you must cast it as Evolving Door's ability resolves. You cannot wait and cast it later.
- 29 April 2022You must pay all costs for a spell you cast this way.
- 29 April 2022Evolving Door's ability instructs you to count the number of colors, but it doesn't track what those colors were. For example, if you sacrifice a creature that is green and no other colors, you'll search for any creature card that is exactly two colors, even if the card you search for isn't green.
- 29 April 2022If you sacrifice a colorless creature, you must search your library for a creature card with exactly one color. If you sacrifice a creature that is all five colors, you won't be able to find any creatures because there are no creature cards in Magic with six colors.