Cheapest priced copy (Commander 2021): $0.69 at Card Kingdom, near mint, their price list as of .
Sproutback Trudge 
Creature — Fungus Beast · 9/7 · Rare · Commander 2021 · #68
This spell costs {X} less to cast, where X is the amount of life you gained this turn.
Trample
At the beginning of your end step, if you gained life this turn, you may cast this creature from your graveyard.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $0.69 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2021 | 68 | Rare | $0.79 | — |
| Commander 2021 | 395 | Rare | $0.69 | — |
5 rulings from Wizards of the Coast
- 16 April 2021You still need to pay the cost to cast Sproutback Trudge from your graveyard.
- 16 April 2021Sproutback Trudge’s ability counts the total amount of life gained without considering any life you lost during that turn. For example, if you lost 3 life and gained 4 life earlier in the turn, Sproutback Trudge will cost {3}{G}{G}.
- 16 April 2021The cost reduction can reduce only generic mana in a spell’s total cost. It can’t reduce the cost to cast Sproutback Trudge beyond {G}{G}.
- 16 April 2021You need to gain life before the end step begins for the last ability to trigger.
- 16 April 2021To determine the total cost of a spell, start with the mana cost or alternative cost you’re paying, add any cost increases, then apply any cost reductions (such as that of Sproutback Trudge’s first ability). Sproutback Trudge’s mana value is always 9, no matter what the total cost to cast the spell was.