Cheapest priced copy (Star Trek): $2.99 at Card Kingdom, near mint, their price list as of .
Engineered Explosives 
Artifact · Rare · Star Trek · #480
Sunburst (This artifact enters with a charge counter on it for each color of mana spent to cast it.)
{2}, Sacrifice this artifact: Destroy each nonland permanent with mana value equal to the number of charge counters on this artifact.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
9 printings · $2.99 to $129.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Double Masters | 252 | Rare | $7.49 | $14.99 |
| Fifth Dawn | 118 | Rare | $9.99 | $79.99 |
| Mystery Booster 2 | 218 | Rare | $5.49 | $24.99 |
| Modern Masters | 204 | Rare | $6.99 | $16.99 |
| Kaladesh Inventions | 36 | Special | — | $129.99 |
| Ultimate Box Topper | U28 | Mythic | — | $22.99 |
| Star Trek | 264 | Rare | $2.99 | $2.99 |
| Star Trek | 480 | Rare | $3.99Out of stock | $4.99Out of stock |
| Ultimate Masters | 227 | Rare | $5.99 | $12.99 |
4 rulings from Wizards of the Coast
- 7 August 2020If a permanent has {X} in its mana cost, X is considered to be 0.
- 7 August 2020Colorless mana won't give Engineered Explosives another charge counter. Colorless is not a color.
- 7 August 2020You can choose any value for X as you cast Engineered Explosives. The value chosen for X doesn't directly affect the number of charge counters Engineered Explosives enters the battlefield with, but it does let you pay more mana and thus spend more colors of mana to cast it.
- 7 August 2020Tokens that aren't a copy of something else don't have a mana cost. Anything without a mana cost normally has a mana value of 0.