Cheapest priced copy (Strixhaven: School of Mages): $0.35 at Card Kingdom, near mint, their price list as of .
Blood Age General 
Creature — Spirit Warrior · 2/2 · Common · Strixhaven: School of Mages · #93
{T}: Attacking Spirits get +1/+0 until end of turn.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Strixhaven: School of Mages | 93 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 16 April 2021Blood Age General’s activated ability affects only Spirits that are attacking as it resolves. If you activate it while no Spirits are attacking, it will have no effect, even if you attack with one or more Spirits later in the turn.
- 16 April 2021Once the activated ability resolves, Spirits that get the +1/+0 bonus will retain it until end of turn, even after they stop attacking or if they stop being Spirits.