Cheapest priced copy (The Lost Caverns of Ixalan): $2.99 at Card Kingdom, near mint, their price list as of .
Tishana's Tidebinder 
Creature — Merfolk Wizard · 3/2 · Rare · The Lost Caverns of Ixalan · #335
Flash
When this creature enters, counter up to one target activated or triggered ability. If an ability of an artifact, creature, or planeswalker is countered this way, that permanent loses all abilities for as long as this creature remains on the battlefield. (Mana abilities can't be targeted.)
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
5 printings · $2.99 to $6.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| The Lost Caverns of Ixalan | 81 | Rare | $3.49 | $4.49 |
| The Lost Caverns of Ixalan | 335 | Rare | $2.99 | $5.99 |
| Japan Standard Cup | 2025-1 | Rare | — | — |
| The Lost Caverns of Ixalan Promos | 81p | Rare | $3.49 | $4.99 |
| The Lost Caverns of Ixalan Promos | 81s | Rare | — | $6.49 |
3 rulings from Wizards of the Coast
- 10 November 2023If the affected permanent gains an ability after Tishana's Tidebinder's effect begins to apply to it, it will keep that ability.
- 10 November 2023Tishana's Tidebinder's triggered ability checks to see if the source of the ability is an artifact, creature, or planeswalker as it resolves. If it isn't, it won't lose all abilities, even if it was an artifact, creature, or planeswalker when the ability was activated or when it triggered.
- 10 November 2023If Tishana's Tidebinder leaves the battlefield before its triggered ability resolves, the target activated or triggered ability will still be countered, but the source of the ability won't lose its abilities at all.