In Romanian, the logic is absolute. Any time you buy something with money, well… you buy it with money.

Ex: Am cumparat cartea lui Sam cu doar 30 de lei!

However in English, as odd as it sounds, and as infrequently as it is used here, one always pays for things (with money).

Ex: I bought an awesome book for only 30 lei
Ex: I paid 20 euros for those shoes.
Ex: I picked up a T-shirt on sale for only 50 lei.

AND NOW YOU KNOW!