Learn Romanian: Această băutură este scumpă.

Această means "this" for feminine nouns. Because the word for drink (băutură) is feminine, we have to use the feminine form. If the noun were masculine or neuter, you would use acest.

Why does the word for expensive (scumpă) end with an -ă here?

Adjectives in Romanian have to match the gender of the noun they describe. The base masculine form is scump, but since băutură is a feminine noun, we must change the adjective to its feminine form, scumpă.

Does această always go right before the noun?

At this level, yes! When demonstrative words like această (this) or acea (that) are placed before the noun, the noun stays in its basic form. Notice how we just use băutură and don't need to add a "the" ending to it.

How can I easily remember that băutură is a feminine noun?

A great clue is the ending! In Romanian, the vast majority of singular nouns that end in the letter -ă are feminine.