Cheapest priced copy (Jumpstart 2022): $0.49 at Card Kingdom, near mint, their price list as of .
Wake Thrasher 
Creature — Merfolk Soldier · 1/1 · Rare · Eventide · #31
Whenever a permanent you control becomes untapped, this creature gets +1/+1 until end of turn.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
4 printings · $0.49 to $7.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Duel Decks: Merfolk vs. Goblins | 24 | Rare | $0.59 | — |
| Eventide | 31 | Rare | $0.99 | $7.99 |
| Jumpstart 2022 | 369 | Rare | $0.49 | — |
| The List | DDT-24 | Rare | $0.49 | — |
One ruling from Wizards of the Coast
- 1 August 2008If permanents you control become untapped during your untap step, Wake Thresher’s ability will trigger that many times. However, since no player gets priority during the untap step, those abilities wait to be put on the stack until your upkeep starts. At that time, all your “beginning of upkeep” triggers will also trigger. You can put them and Wake Thresher’s abilities on the stack in any order.