This is the 628th most frequent Latvian word.
nauda
Money.
In this sentence, 'nauda' refers to financial currency needed to cover payments.
Man ir nepieciešama nauda, lai samaksātu par dzīvokli.
I need money to pay for the apartment.
Here, 'naudas' is the possessive singular genitive form of 'nauda', used to specify the sufficient amount of money.
Vai tev pietiek naudas grāmatas iegādei?
Do you have enough money to buy a book?
In this context, 'naudu' is in the accusative case, used to indicate the direct object of the verb 'lost'.