Cheapest priced copy (Battle for Zendikar): $0.79 at Card Kingdom, near mint, their price list as of .
Beastcaller Savant 
Creature — Elf Shaman Ally · 1/1 · Rare · Battle for Zendikar · #170
Haste
{T}: Add one mana of any color. Spend this mana only to cast a creature spell.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.79 to $4.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Battle for Zendikar | 170 | Rare | $0.79 | $2.99 |
| Battle for Zendikar Promos | 170s | Rare | — | $4.99 |
2 rulings from Wizards of the Coast
- 25 August 2015Mana produced by Beastcaller Savant can be spent on any part of a creature spell’s total cost, including additional costs (such as kicker costs) and alternative costs (such as dash costs). It can’t be spent to pay the costs of abilities of creatures you control.
- 25 August 2015Mana produced by Beastcaller Savant can’t be used to activate an ability or cast an instant or sorcery spell that creates creature tokens.