Answer: token

AnswerCrossword Clue
TOKEN

Keepsake

TOKEN

Keepsake or souvenir

TOKEN

Bus fare

TOKEN
Subway fare
TOKEN
Only black child in "South Park"
TOKENBlack kid on "South Park"
TOKENTurnstile coin
TOKENTransit fare
TOKENFare, often
TOKENCoin stand-in
TOKENSmall memento
TOKENBus coin
TOKENMemento
TOKENBattleship on a Monopoly board, e.g.
TOKENTurnstile insert
TOKENArcade coin
TOKENPerfunctory
TOKENSymbolic yet insubstantial
TOKENSubway turnstile feeder
TOKENKind of agreement
TOKENSmall gift of appreciation
TOKENBy the same ...
TOKENSubway slug
TOKENBus payment, often
TOKENIron or top hat, in "Monopoly"
TOKENCurrency substitute, perhaps
TOKENNYC subway fare, once
TOKENSubway coin
TOKENGame piece
TOKENCoin for a game of Skee-Ball, perhaps
TOKENSubway rider's need, maybe
TOKENCoin substitute
TOKENFare piece
TOKENStraphanger's need
TOKENSubway rider's need
TOKENEvidence of esteem?
TOKENMemorable symbol
TOKENSymbol
TOKENStraphanger's buy
TOKENArcade disk