Cheapest priced copy (Duel Decks: Merfolk vs. Goblins): $0.99 at Card Kingdom, foil, near mint, their price list as of .
Master of Waves 
Creature — Merfolk Wizard · 2/1 · Mythic · Secret Lair Drop · #1278
Protection from red
Elemental creatures you control get +1/+1.
When this creature enters, create a number of 1/0 blue Elemental creature tokens equal to your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $0.99 to $4.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Duel Decks: Merfolk vs. Goblins | 1 | Mythic | — | $0.99 |
| The List | DDT-1 | Mythic | $0.99 | — |
| Secret Lair Drop | 1278 | Mythic | $2.29 | $4.49 |
| Theros | 53 | Mythic | $0.99 | $4.49 |
7 rulings from Wizards of the Coast
- 15 September 2013Barring other effects, the Elemental tokens will enter the battlefield as 2/1 creatures.
- 15 September 2013If Master of Waves leaves the battlefield, and nothing else is raising the toughness of the Elemental tokens above 0, the Elemental tokens will die and subsequently cease to exist.
- 15 September 2013Numeric mana symbols ({0}, {1}, and so on) in mana costs of permanents you control don't count toward your devotion to any color.
- 15 September 2013Hybrid mana symbols, monocolored hybrid mana symbols, and Phyrexian mana symbols do count toward your devotion to their color(s).
- 15 September 2013Use your devotion to blue as the triggered ability resolves to determine how many tokens are put onto the battlefield. If Master of Waves is still on the battlefield at that time, its mana cost will count toward your devotion to blue.
- 15 September 2013Mana symbols in the text boxes of permanents you control don't count toward your devotion to any color.
- 15 September 2013If an activated ability or triggered ability has an effect that depends on your devotion to a color, you count the number of mana symbols of that color among the mana costs of permanents you control as the ability resolves. The permanent with that ability will be counted if it's still on the battlefield at that time.