Cheapest priced copy (Modern Horizons 2 Timeshifts): $0.39 at Card Kingdom, near mint, their price list as of .
Abiding Grace 
Enchantment · Uncommon · Modern Horizons 2 Timeshifts · #1
At the beginning of your end step, choose one —
• You gain 1 life.
• Return target creature card with mana value 1 from your graveyard to the battlefield.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $0.39 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Horizons 2 Timeshifts | 1 | Uncommon | $0.39 | $0.49 |
| Modern Horizons 2 | 1 | Uncommon | $0.39 | $0.49 |
One ruling from Wizards of the Coast
- 18 June 2021If a creature card in your graveyard has {X} in its mana cost, X is 0 when determining its mana value.