Cheapest priced copy (Theros): $0.35 at Card Kingdom, near mint, their price list as of .
Two-Headed Cerberus 
Creature — Dog · 1/2 · Common · Theros · #146
Double strike (This creature deals both first-strike and regular combat damage.)
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Theros | 146 | Common | $0.35 | $0.49 |