Cheapest priced copy (Aetherdrift): $0.35 at Card Kingdom, near mint, their price list as of .
Boom Scholar 
Creature — Goblin Advisor · 3/3 · Uncommon · Aetherdrift · #189
Exhaust abilities of other permanents you control cost {2} less to activate.
Exhaust — {4}{R}{G}: Creatures and Vehicles you control gain trample until end of turn. Put two +1/+1 counters on this creature. (Activate each exhaust ability only once.)
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Aetherdrift | 189 | Uncommon | $0.35 | $0.49 |
4 rulings from Wizards of the Coast
- 7 February 2025If an ability triggers whenever you activate an exhaust ability, that ability resolves before the exhaust ability resolves.
- 7 February 2025If an exhaust ability of a permanent is activated, and then that permanent leaves the battlefield and returns to the battlefield, it becomes a new object so its exhaust ability can be activated again.
- 7 February 2025Exhaust abilities can be activated any time you could normally activate an ability.
- 7 February 2025Boom Scholar’s first ability can cause the mana component of the cost to activate an ability to be {0}.