Cheapest priced copy (Commander Legends: Battle for Baldur's Gate): $17.99 at Card Kingdom, near mint, their price list as of .
Frenzy of the Fireys 
Delayed Blast Fireball
Instant · Rare · Secret Lair Drop · #2847
Delayed Blast Fireball deals 2 damage to each opponent and each creature they control. If this spell was cast from exile, it deals 5 damage to each opponent and each creature they control instead.
Foretell {4}{R}{R} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
4 printings · $17.99 to $20.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander Legends: Battle for Baldur's Gate | 630 | Rare | $17.99 | — |
| Commander Legends: Battle for Baldur's Gate | 676 | Rare | $17.99 | — |
| Secret Lair Drop | 1824 | Rare | $17.99 | $20.99 |
| Secret Lair Drop (Frenzy of the Fireys) | 2847 | Rare | — | — |
4 rulings from Wizards of the Coast
- 10 June 2022Because exiling a card with foretell from your hand is a special action, you can do so any time you have priority during your turn, including in response to spells and abilities. Once you announce you're taking the action, no other player can respond by trying to remove the card from your hand.
- 10 June 2022Delayed Blast Fireball deals 5 damage if it was cast from exile for any reason; it doesn't have to be from its foretell ability.
- 10 June 2022If you're casting a foretold card from exile for its foretell cost, you can't choose to cast it for any other alternative costs. You can, however, pay additional costs, such as kicker costs. If the card has any mandatory additional costs, those must be paid to cast the spell.
- 10 June 2022Casting a foretold card from exile follows the timing rules for that card. If you foretell an instant card, you can cast it as soon as the next player's turn. In most cases, if you foretell a card that isn't an instant (or doesn't have flash), you'll have to wait until your next turn to cast it.