Kirby's Return to Dream Land
The first appearance of score coins is in the Challenge Stages playable from within the Lor Starcutter. They come in silver and gold varieties, worth 100 and 1000 points respectively. They resemble round Roman-style coins, but bear stars on them instead of faces.
Collecting every coin in the stage confers upon Kirby an additional bonus.
Kirby's Dream Collection Special Edition
The New Challenge Stages Sub-Game is an extension of the earlier Challenge stages from Return to Dream Land. The coins in these stages likewise are the same, and serve the same purpose.
One thing to note is that during the Magolor Races, Magolor is capable of picking up these coins as well. If he gets them, they will become unavailable to Kirby.
Kirby: Triple Deluxe and Dedede's Drum Dash Deluxe
In both the original Dedede's Drum Dash and its deluxe version, coins can be collected along the path, and a bonus is conferred if all of them are collected in a given stage. Unlike in the Challenge Stages, the coins here resemble traditional Yen coins.
Kirby: Planet Robobot and Kirby's Blowout Blast
In both Kirby 3D Rumble and Kirby's Blowout Blast, coins are scattered across the stage, and earn points when collected. They resemble the ones in Dedede's Drum Dash. Coins here come in three types; bronze are worth 100 points, silver 500 points, and gold 3000 points.