Cheapest priced copy (Modern Horizons): $5.49 at Card Kingdom, near mint, their price list as of .
Unsettled Mariner 
Creature — Shapeshifter · 2/2 · Rare · The List · #MH1-216
Changeling (This card is every creature type.)
Whenever you or a permanent you control becomes the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {1}.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $5.49 to $11.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Horizons | 216 | Rare | $5.49 | $11.99 |
| The List | MH1-216 | Rare | $5.99 | — |
2 rulings from Wizards of the Coast
- 14 June 2019If you and a permanent you control each become the targets of the same spell or ability an opponent controls, Unsettled Mariner’s ability will trigger twice. The same is true if two permanents you control each become the targets of the same spell or ability an opponent controls.
- 14 June 2019If a spell or ability an opponent controls targets only you or only one permanent you control, but it targets you or that permanent multiple times, Unsettled Mariner’s ability triggers only once.