Cheapest priced copy (Zendikar): $8.99 at Card Kingdom, near mint, their price list as of .
Lullmage Mentor 
Creature — Merfolk Wizard · 2/2 · Rare · Zendikar · #54
Whenever a spell or ability you control counters a spell, you may create a 1/1 blue Merfolk creature token.
Tap seven untapped Merfolk you control: Counter target spell.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $8.99 to $22.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Zendikar | 54 | Rare | $8.99 | $22.99 |
3 rulings from Wizards of the Coast
- 1 October 2009A spell or ability counters a spell only if it specifically contains the word “counter” in its text. If a spell or ability you control causes all the targets of a spell to become illegal, that spell doesn’t resolve but is not countered.
- 1 October 2009Lullmage Mentor’s second ability will cause its first ability to trigger.
- 1 October 2009Since the second ability doesn’t have a tap symbol in its cost, you can tap creatures (including Lullmage Mentor itself) that haven’t been under your control since your most recent turn began to pay the cost.