Cheapest priced copy (Modern Masters 2015): $0.35 at Card Kingdom, near mint, their price list as of .
Stoic Rebuttal 
Instant · Common · Scars of Mirrodin · #46
Metalcraft — This spell costs {1} less to cast if you control three or more artifacts.
Counter target spell.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
2 printings · $0.35 to $1.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Masters 2015 | 59 | Common | $0.35 | $0.99 |
| Scars of Mirrodin | 46 | Common | $0.35 | $1.99 |
2 rulings from Wizards of the Coast
- 1 January 2011Stoic Rebuttal’s metalcraft ability functions while Stoic Rebuttal is on the stack.
- 1 January 2011For the purpose of determining whether the cost reduction applies, the number of artifacts you control is checked as you cast Stoic Rebuttal, before your last chance to activate mana abilities to pay for it. For example, if you control three artifacts, you could determine that Stoic Rebuttal costs {U}{U} to cast, then sacrifice one of those artifacts to activate a mana ability.