noun-modifying (irregular)
one-coin; costing a single coin
Typically refers to something that can be paid for with a single 500-yen coin, sometimes a 100-yen coin. Used prenominally in phrases like ワンコインランチ.
That shop's one-coin lunch is a great deal.
ワンコインで楽しめるイベントを探している。
I'm looking for an event I can enjoy for just one coin.
From English 'one coin', referring to a single coin payment, typically a 500-yen coin in Japan.