Place it at the exact frame a reward appears, after the Mario Jump for a full game sequence and before an air horn for a bigger win. Use the Bell Ding for a second, smaller pickup so the coin stays the main payoff.
About this sound
This under-a-second clip is the bright coin collection chime from Super Mario Bros. 3, a quick arcade ping that sounds like an instant reward. It feels cheerful and satisfying, with a nostalgic spark for anyone who grew up with retro games. The effect comes from the NES platform game, where it played whenever Mario collected a coin.