Learn Romanian: Un dicționar bun costă o sută de lei. - A good dictionary costs one hundred lei.

In Romanian, when you count things using numbers from 20 onwards (except numbers ending in 1 to 19), you must put the linking word de between the number and the noun. Because 100 is 20 or higher and doesn't end in 1-19, it requires de before lei.

Why do we say o sută instead of un sută for one hundred?

The word for hundred, sută, is a feminine noun in Romanian. Therefore, it must be paired with the feminine form for one, which is o. You are literally saying 'a hundred'.

Why is the adjective bun placed after dicționar?

In Romanian, descriptive adjectives like bun (good) usually come right after the noun they describe. While English says 'a good dictionary', Romanian literally says 'a dictionary good'.

Since dicționar uses un, does that mean it is a masculine noun?

Dicționar is actually a neuter noun. Neuter nouns behave like masculine nouns in the singular, which is why it takes un and the masculine adjective bun. If we talked about multiple dictionaries, it would behave like a feminine noun.

Does the verb costă change if we are talking about multiple dictionaries?