FOILCheapest priced copy (Reality Fracture Commander): $0.49 at Card Kingdom, near mint, their price list as of .
Sunfall 
Sorcery · Rare · March of the Machine Promos · #40s
Exile all creatures. Incubate X, where X is the number of creatures exiled this way. (Create an Incubator token with X +1/+1 counters on it and "{2}: Transform this token." It transforms into a 0/0 Phyrexian artifact creature.)
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
5 printings · $0.49 to $2.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Reality Fracture Commander | 36 | Rare | $0.49 | — |
| March of the Machine | 40 | Rare | $0.69 | $0.99 |
| March of the Machine | 349 | Rare | $2.29 | $1.99 |
| March of the Machine Promos | 40p | Rare | $0.69 | $1.99 |
| March of the Machine Promos | 40s | Rare | — | $2.49 |
One ruling from Wizards of the Coast
- 14 April 2023If Sunfall resolves but doesn't exile any creatures, you'll incubate 0, creating an Incubator token but putting no +1/+1 counters on it. It will still have the ability to transform, but you might need to figure out how it's going to survive first.