Cheapest priced copy (March of the Machine Commander): $2.79 at Card Kingdom, near mint, their price list as of .
Deluxe Dragster 
Artifact — Vehicle · 4/3 · Rare · March of the Machine Commander · #108
This Vehicle can't be blocked except by Vehicles.
Whenever this Vehicle deals combat damage to a player, you may cast target instant or sorcery card from that player's graveyard without paying its mana cost. If that spell would be put into a graveyard, exile it instead.
Crew 2
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $2.79 to $2.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| March of the Machine Commander | 21 | Rare | $2.79 | — |
| March of the Machine Commander | 108 | Rare | $2.99 | — |
3 rulings from Wizards of the Coast
- 14 April 2023If you cast the instant or sorcery card, you do so as part of the resolution of the triggered ability. You can't wait to cast them later in the turn. Timing restrictions based on a card's type are ignored.
- 14 April 2023If an exiled card has {X} in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.
- 14 April 2023If you cast a card "without paying its mana cost," you can't pay any alternative costs. You can, however, pay additional costs. If the card has any mandatory additional costs, those must be paid to cast the card.