Cheapest priced copy (The Lost Caverns of Ixalan): $2.29 at Card Kingdom, near mint, their price list as of .
Saheeli, the Sun's Brilliance 
Legendary Creature — Human Artificer · 2/2 · Mythic · The Lost Caverns of Ixalan · #239
{U}{R}, {T}: Create a token that's a copy of another target creature or artifact you control, except it's an artifact in addition to its other types. It gains haste. Sacrifice it at the beginning of the next end step.
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
5 printings · $2.29 to $6.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| The Lost Caverns of Ixalan | 239 | Mythic | $2.29 | $2.49 |
| The Lost Caverns of Ixalan | 308 | Mythic | $2.49 | $2.99 |
| The Lost Caverns of Ixalan Promos | 239p | Mythic | $2.79 | $6.99 |
| The Lost Caverns of Ixalan Promos | 239s | Mythic | — | $2.99 |
| Planeswalker Championship Promos | 2024-05 | Mythic | — | — |
5 rulings from Wizards of the Coast
- 10 November 2023Any enters-the-battlefield abilities of the copied permanent will trigger when the token enters the battlefield. Any "as [this permanent] enters the battlefield" or "[this permanent] enters the battlefield with" abilities of the target permanent will also work.
- 10 November 2023If the copied permanent is a token, the new token that's created copies the original characteristics of that token as stated by the effect that created the token (with the listed exceptions).
- 10 November 2023If the copied permanent has {X} in its mana cost, X is 0.
- 10 November 2023If the copied permanent is copying something else, then the token enters the battlefield as whatever that permanent copied (with the listed exceptions).
- 10 November 2023The token copies exactly what was printed on the original permanent, with the listed exceptions (unless that permanent is copying something else or is a token; see below). It doesn't copy whether that permanent is tapped or untapped, whether it has any counters on it or any Auras or Equipment attached to it, or any non-copy effects that have changed its types, color, power and toughness, and so on.