Cheapest priced copy (RNA Guild Kit): $8.99 at Card Kingdom, near mint, their price list as of .
Protean Hulk 
Creature — Beast · 6/6 · Rare · Masters 25 · #185
When this creature dies, search your library for any number of creature cards with total mana value 6 or less, put them onto the battlefield, then shuffle.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
8 printings · $8.99 to $54.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Masters 25 | 185 | Rare | $9.49 | $14.99 |
| Dissension | 90 | Rare | $9.99 | $54.99 |
| RNA Guild Kit | 83 | Rare | $8.99 | — |
| Ravnica Remastered | 153 | Mythic | $10.99 | $10.99 |
| Ravnica Remastered | 353 | Mythic | $9.49 | $22.99 |
| Ravnica Remastered | 353z | Mythic | — | — |
| Ravnica Remastered | 435 | Mythic | $12.99 | $37.99 |
| Secret Lair Drop | 319 | Rare | $12.99 | — |
2 rulings from Wizards of the Coast
- 16 March 2018You can find any number of creature cards, so long as their total mana value is 6 or less. For example, you could find eight creature cards with mana value 0 and three with mana value 2, but you couldn't find two with mana value 4.
- 16 March 2018If a card in your library has {X} in its mana cost, X is considered to be 0.