This is the 11488th most frequent Polish word.
jednorazowa
"Jednorazowa" means "disposable" or "single-use" in English.
The word 'jednorazową' in this sentence is an adjective describing the razor, indicating that it is intended for single-use only.
Kupiłem jednorazową maszynkę do golenia.
I bought a disposable razor.
Here, 'jednorazowa' is used as an adjective describing the sum, implying that the transaction occurs only once.
Jednorazowa suma została odliczona z konta.
A one-time sum was deducted from the account.
In this context, 'jednorazowej' qualifies the offer, suggesting that it is an exclusive opportunity available only once.