Cheapest priced copy (Jumpstart): $0.35 at Card Kingdom, near mint, their price list as of .
Cathar's Companion 
Creature — Dog · 3/1 · Common · Shadows over Innistrad · #9
Whenever you cast a noncreature spell, this creature gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
3 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Jumpstart | 94 | Common | $0.35 | — |
| The List | SOI-9 | Common | $0.35 | — |
| Shadows over Innistrad | 9 | Common | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 8 April 2016Cathar’s Companion’s triggered ability resolves before the spell that caused it to trigger.