Cheapest priced copy (Journey into Nyx): $0.35 at Card Kingdom, near mint, their price list as of .
Oppressive Rays 
Enchantment — Aura · Common · Magic 2015 · #21
Enchant creature
Enchanted creature can't attack or block unless its controller pays {3}.
Activated abilities of enchanted creature cost {3} more to activate.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Journey into Nyx | 19 | Common | $0.35 | $0.49 |
| Magic 2015 | 21 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 18 July 2014Activated abilities are written in the form “Cost: Effect.” Some keywords are activated abilities and will have colons in their reminder texts. Static and triggered abilities are unaffected by Oppressive Rays.
- 18 July 2014The enchanted creature's controller can choose to not attack or block with it even if it must attack or block if able. Players can't be forced to pay a cost to attack or block.