Emerge is a keyword ability that lets you cast a spell for an alternative cost by sacrificing a creature and reducing the emerge cost by that creature's converted mana cost (mana value). The rules for emerge are found in CR 702.134. Nothing in the emerge rules requires the sacrificed creature to be a nontoken creature.
Tokens are creature permanents while they exist on the battlefield (CR 111.1, 111.7). They have a power, toughness, and mana value just like nontoken creatures. Because emerge only requires you to 'sacrifice a creature,' and tokens are creatures, tokens are perfectly legal sacrifices for emerge.
The mana value of a token is typically 0 unless it was created by a spell or ability that defined its mana cost (CR 202.3a). So in most cases, sacrificing a token reduces the emerge cost by 0, meaning you pay the full emerge cost — but the sacrifice is still legal.
Concrete example: You control a Saproling token (a 1/1 creature with no mana cost, mana value 0). You want to cast Elder Deep-Fiend, which has emerge 6 (its total cost is 8). You sacrifice the Saproling: the emerge cost is reduced by the token's mana value (0), so you pay 6 generic mana. The cast is completely legal.
If you somehow have a token with a defined mana cost — for example, a token copy of a creature with a mana cost — its mana value would be calculated from that cost and would reduce the emerge cost accordingly (CR 202.3a, 111.4).
Unofficial fan resource — not affiliated with or endorsed by Wizards of the Coast. Answers are AI-generated estimates grounded in the Comprehensive Rules and are not a substitute for an official judge. Verify anything match-critical.