Learn Swedish: Vi vill ha extra biljetter, men de är inte gratis. - We want extra tickets, but they are not free.

Gratis (free) is an indeclinable adjective. This means its spelling is locked in place. It never changes its ending, regardless of whether the noun it describes is an en-word, an ett-word, or plural.

Is extra also an indeclinable adjective here?

Exactly! Even though it describes the plural noun biljetter (tickets), it stays exactly the same. Adjectives that already end in a vowel, like extra, bra (good), and äkta (genuine), are usually indeclinable and never take plural or ett-word endings.

Why do we use vill ha instead of just vill for want?

In Swedish, vill is used when you want to do an action (like vi vill åka, we want to go). When you want a physical thing or an object, like tickets, you must use vill ha, which literally translates to want to have.

How is the word de pronounced in this sentence?

De is the proper written word for they. However, in almost all spoken Swedish, it is pronounced as dom. When reading this sentence aloud, you should say dom är inte gratis.