Cheapest priced copy (Final Fantasy Commander): $0.49 at Card Kingdom, near mint, their price list as of .
Lethal Scheme 
Instant · Rare · The Lost Caverns of Ixalan Commander · #201
Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Destroy target creature or planeswalker. Each creature that convoked this spell connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on that creature.)
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
13 printings · $0.49 to $19.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Final Fantasy Commander | 277 | Rare | $0.49 | $1.99 |
| The Lost Caverns of Ixalan Commander | 201 | Rare | $0.69 | — |
| Marvel Super Heroes Commander | 157 | Rare | $0.49 | $0.49 |
| Marvel Super Heroes Commander | 353 | Rare | $1.79 | — |
| New Capenna Commander | 36 | Rare | $0.59 | — |
| New Capenna Commander | 137 | Rare | $1.99 | — |
| Fallout | 185 | Rare | $0.49 | $0.99 |
| Fallout | 464 | Rare | $1.79 | $1.49 |
| Fallout | 713 | Rare | — | $1.99 |
| Fallout | 992 | Rare | — | $3.49 |
| New Capenna Commander Promos | 36p | Rare | — | $19.99 |
| Secret Lair Drop | 2187 | Rare | $8.99Out of stock | $10.99 |
| Tarkir: Dragonstorm Commander | 184 | Rare | $0.49 | — |
11 rulings from Wizards of the Coast
- 29 April 2022If a resolving spell or ability instructs a specific creature to connive but that creature has left the battlefield, the creature still connives. If you discard a nonland card this way, you won't put a +1/+1 counter on anything. Abilities that trigger "when [that creature] connives" will trigger.
- 29 April 2022Once an ability that causes a creature to connive begins to resolve, no player may take any other actions until it's done. Notably, opponents can't try to remove the conniving creature after you discard a nonland card but before it receives a counter.
- 29 April 2022You can't tap more creatures to convoke Lethal Scheme than it takes to pay for its total cost. This means that normally no more than four creatures can convoke it.
- 29 April 2022When multiple creatures are instructed to connive simultaneously, they connive one at a time in the order of their controller's choice.
- 29 April 2022If no card is discarded, most likely because that player's hand is empty and an effect says they can't draw cards, the conniving creature does not receive a +1/+1 counter.
- 12 January 2024When 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. Convoke applies after the total cost is calculated. Convoke doesn't change a spell's mana cost or mana value.
- 12 January 2024Because convoke isn't an alternative cost, it can be used in conjunction with alternative costs.
- 12 January 2024If a creature you control has a mana ability with {T} in the cost, activating that ability while casting a spell with convoke will result in the creature being tapped before you pay the spell's costs. You won't be able to tap it again for convoke. Similarly, if you sacrifice a creature to activate a mana ability while casting a spell with convoke, that creature won't be on the battlefield when you pay the spell's costs, so you won't be able to tap it for convoke.
- 12 January 2024Tapping an untapped creature that's attacking or blocking to convoke a spell won't cause that creature to stop attacking or blocking.
- 12 January 2024You can tap any untapped creature you control to convoke a spell, even one you haven't controlled continuously since the beginning of your most recent turn.
- 12 January 2024Tapping a multicolored creature using convoke will pay for {1} or one mana of your choice of any of that creature's colors.