Cheapest priced copy (Ravnica Allegiance): $0.35 at Card Kingdom, near mint, their price list as of .
Combine Guildmage 
Creature — Merfolk Wizard · 2/2 · Uncommon · Ravnica Allegiance · #163
{1}{G}, {T}: This turn, each creature you control enters with an additional +1/+1 counter on it.
{1}{U}, {T}: Move a +1/+1 counter from target creature you control onto another target creature you control.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Ravnica Allegiance | 163 | Uncommon | $0.35 | $0.49 |
3 rulings from Wizards of the Coast
- 25 January 2019If either target creature is an illegal target by the time Combine Guildmage’s second ability tries to resolve, nothing happens. No creature loses or gets a +1/+1 counter.
- 25 January 2019If a creature would normally enter the battlefield with no +1/+1 counters on it, Combine Guildmage’s first ability causes it to enter the battlefield with a +1/+1 counter on it.
- 25 January 2019If the first target creature for Combine Guildmage’s second ability has no +1/+1 counters on it as the ability resolves, nothing happens. The second target creature doesn’t get a +1/+1 counter.