Cheapest priced copy (Strixhaven: School of Mages): $0.35 at Card Kingdom, near mint, their price list as of .
Expanded Anatomy 
Sorcery — Lesson · Common · Strixhaven: School of Mages · #2
Put two +1/+1 counters on target creature. It gains vigilance 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 | 2 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 16 April 2021Although you may want to include Lessons in your sideboard if you’re playing with cards that instruct you to learn, Lesson cards can be included in your main deck like other instant or sorcery cards.
- 16 April 2021Lesson is a spell subtype found on some instant and sorcery cards in the Strixhaven set. The Lesson subtype has no special rules associated with it.