Cheapest priced copy (Core Set 2019): $0.69 at Card Kingdom, near mint, their price list as of .
Mirror Image 
Creature — Shapeshifter · 0/0 · Uncommon · Core Set 2019 · #61
You may have this creature enter as a copy of a creature you control.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
3 printings · $0.69 to $14.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Jumpstart 2022 | 62 | Uncommon | $14.99 | — |
| Core Set 2019 | 61 | Uncommon | $0.69 | $3.49 |
| The List | M19-61 | Uncommon | $0.69 | — |
6 rulings from Wizards of the Coast
- 13 July 2018If the chosen creature is copying something else (for example, if the chosen creature is another Mirror Image), then Mirror Image enters the battlefield as whatever the chosen creature copied.
- 13 July 2018Any enters-the-battlefield abilities of the copied creature will trigger when Mirror Image enters the battlefield. Any "as [this creature] enters the battlefield" or "[this creature] enters the battlefield with" abilities of the chosen creature will also work.
- 13 July 2018If Mirror Image somehow enters the battlefield at the same time as another creature, it can't become a copy of that creature. You may choose only a creature that's already on the battlefield.
- 13 July 2018Mirror Image copies exactly what was printed on the original creature (unless that creature is copying something else or is a token; see below). It doesn't copy whether that creature is tapped or untapped, whether it has any counters on it or any Auras and Equipment attached to it, or any non-copy effects that have changed its power, toughness, types, color, or so on.
- 13 July 2018If the copied creature has {X} in its mana cost, X is considered to be 0.
- 13 July 2018If the chosen creature is a token, Mirror Image copies the original characteristics of that token as stated by the effect that put the token onto the battlefield. Mirror Image doesn't become a token in this case.