not cost a penny

: the amount or equivalent paid or charged for something : price

: the outlay or expenditure (as of effort or sacrifice) made to achieve an object

: loss or penalty incurred especially in gaining something

: to require expenditure or payment

: to require effort, suffering, or loss

: to have a price of

: a monetary unit of the United Kingdom formerly equal to ¹/₂₄₀ pound but now equal to ¹/₁₀₀ pound

: a similar monetary unit of any of various other countries in or formerly in the Commonwealth of Nations — see pound at Money Table

: a coin representing one penny

: being a (designated) nail size