Cheapest priced copy (Urza's Legacy): $0.39 at Card Kingdom, near mint, their price list as of .
Aura Flux 
Enchantment · Common · Urza's Legacy · #27
Other enchantments have "At the beginning of your upkeep, sacrifice this enchantment unless you pay {2}."
Legal inCommanderLegacyVintagePauper
Not legal inBrawlStandardPioneerModern
1 printing · $0.39 to $14.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Urza's Legacy | 27 | Common | $0.39 | $14.99 |
3 rulings from Wizards of the Coast
- 4 October 2004If two or more Aura Fluxes are on the battlefield, they will give the text to each other. And they will cause each other enchantment to have two triggered abilities for which the player would have to pay.
- 4 October 2004You choose whether to pay {2} or not on resolution. If not, then you sacrifice the enchantment.
- 4 October 2004This card adds a triggered ability to all other enchantments.