Cheapest priced copy (Dragons of Tarkir): $0.35 at Card Kingdom, near mint, their price list as of .
Skywise Teachings 
Enchantment · Uncommon · Dragons of Tarkir · #79
Whenever you cast a noncreature spell, you may pay {1}{U}. If you do, create a 2/2 blue Djinn Monk creature token with flying.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Dragons of Tarkir | 79 | Uncommon | $0.35 | $0.49 |
| Iconic Masters | 73 | Uncommon | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 17 November 2017While resolving the triggered ability of Skywise Teachings, you can’t pay {1}{U} multiple times to create more tokens.