This is the 12659th most frequent Russian word.
копейку
The Russian word "копейку" means "kopeck," a monetary unit equal to 1/100th of a Russian ruble.
Here, 'копейку' refers to the specific coin of value 'one kopeck', used in the context of saving or monetary actions.
Он бросил копейку в копилку.
He tossed a kopeck into the piggy bank.
In this usage, 'копейку' refers to an insignificant amount of money, figuratively implying that the cost or value is very low.
Этот старый автомобиль стоит копейку.
This old car costs a kopeck.
Here, 'копейки' (a grammatical inflection of 'копейку') symbolizes a unit measure of profit or money, used metaphorically to indicate absence of earnings.