Buck, US-Dollar. Loan word from American English (“bucks”), but it is considered as a singular in Russian. Plural is баксы.
Доллар США идет на дно: извлекать баксы из чулков и менять их уже безнадежно поздно.
The US dollar is going down: it’s already hopelessly late to get your bucks from under the mattress and change them.