Cheapest priced copy (Commander Masters): $0.49 at Card Kingdom, near mint, their price list as of .
Shimmer Myr 
Artifact Creature — Myr · 2/2 · Uncommon · Commander Masters · #409
Flash
You may cast artifact spells as though they had flash.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
7 printings · $0.49 to $15.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2016 | 269 | Rare | $0.99 | — |
| Commander Masters | 409 | Uncommon | $0.49 | $0.99 |
| Commander Legends | 339 | Uncommon | $0.49 | $0.99 |
| Foundations Commander | 283 | Uncommon | $0.49 | — |
| Mirrodin Besieged | 129 | Rare | $0.69 | $15.99 |
| March of the Machine Commander | 376 | Uncommon | $0.49 | — |
| Neon Dynasty Commander | 157 | Uncommon | $0.49 | — |
2 rulings from Wizards of the Coast
- 10 November 2020Shimmer Myr has no effect on artifact lands because they aren't cast as spells.
- 10 November 2020Once you announce that you're casting a spell, players can't attempt to remove Shimmer Myr from the battlefield to make that casting illegal. Removing Shimmer My after you've cast a spell won't affect that spell.