Cheapest priced copy (Double Masters): $0.35 at Card Kingdom, near mint, their price list as of .
Metallic Rebuke 
Instant · Common · Aether Revolt · #39
Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Counter target spell unless its controller pays {3}.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
3 printings · $0.35 to $8.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Double Masters | 59 | Common | $0.35 | $1.49 |
| Aether Revolt | 39 | Common | $0.35 | $8.99 |
| The List | AER-39 | Common | $0.59 | — |
6 rulings from Wizards of the Coast
- 7 August 2020Tapping an artifact won't cause its abilities to stop applying unless those abilities say so.
- 7 August 2020If an artifact you control has a mana ability with {T} in the cost, activating that ability while casting a spell with improvise will result in the artifact being tapped when you pay the spell's costs. You won't be able to tap it again for improvise. Similarly, if you sacrifice an artifact to activate a mana ability while casting a spell with improvise, that artifact won't be on the battlefield when you pay the spell's costs, so you won't be able to tap it for improvise.
- 7 August 2020Improvise doesn't change a spell's mana cost or mana value.
- 7 August 2020Equipment attached to a creature doesn't become tapped when that creature becomes tapped, and tapping that Equipment doesn't cause the creature to become tapped.
- 7 August 2020When calculating a spell's total cost, include any alternative costs, additional costs, or anything else that increases or reduces the cost to cast the spell. Improvise applies after the total cost is calculated.
- 7 August 2020Improvise can't pay for {U} in Metallic Rebuke's total cost.