Cheapest priced copy (Alara Reborn): $0.49 at Card Kingdom, near mint, their price list as of .
Spellbound Dragon 
Creature — Dragon · 3/5 · Rare · Alara Reborn · #90
Flying
Whenever this creature attacks, draw a card, then discard a card. This creature gets +X/+0 until end of turn, where X is the discarded card's mana value.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
3 printings · $0.49 to $3.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Alara Reborn | 90 | Rare | $0.49 | $3.99 |
| Commander 2017 | 196 | Rare | $0.79 | — |
| The List | ARB-90 | Rare | $0.69 | — |
One ruling from Wizards of the Coast
- 1 May 2009You'll discard a card even if some other effect replaces the draw.