A Dollar Sign is from the short-lived 80s game show Wipeout.
Seen close-up mostly in Round 1, when one of the three contestants selects a correct answer from the monitor, a dollar sign would appear. Each correct answer awarded money for the player. The first correct answer of the round was worth $25 and the value of each subsequent answer increased by $25 with the last one was worth $275.
For the remainder of the show, the dollar sign only indicates that the correct answer was chosen.