Per quel volo economico ci vogliono ottanta euro.

Because ci vuole / ci vogliono is a very common way to say it takes / you need in Italian.

So:

• Il volo costa ottanta euro = The flight costs eighty euros
• Per quel volo ci vogliono ottanta euro = You need eighty euros for that flight

Both can refer to price, but the nuance is slightly different:

• costare focuses on the item's price
• volerci focuses on the amount needed

In this sentence, Italian is expressing the idea to get that cheap flight, eighty euros are needed.

Here ci vogliono comes from the verb volerci, an idiomatic expression meaning:

• to be needed
• to take (time, money, effort, etc.)

Examples:

• Ci vuole tempo. = It takes time.
• Ci vogliono due ore. = It takes two hours.
• Ci vogliono ottanta euro. = Eighty euros are needed / It takes eighty euros.

So in your sentence, ci vogliono ottanta euro means eighty euros are needed.

Because the verb agrees with the thing that is needed.

Here, the grammatical subject is ottanta euro, which is plural in Italian, so you use the plural verb:

• Ci vuole un euro. = One euro is needed
• Ci vogliono ottanta euro. = Eighty euros are needed

So:

• singular thing needed → ci vuole
• plural thing needed → ci vogliono

Even though English often says it takes, Italian makes the verb agree with the noun that follows.

In this expression, ci is part of the idiomatic construction volerci. You usually learn it as a whole chunk:

• ci vuole
• ci vogliono

It does not translate neatly word-for-word in this sentence. You should think of ci vogliono as a fixed expression meaning are needed or it takes.

So it is better not to analyze it too literally as there/us/here. In this pattern, just remember:

• ci vuole + singular noun
• ci vogliono + plural noun

Here per means for.

So:

• Per quel volo economico = For that cheap flight / For that budget flight

It introduces what the money is needed for.

Similar examples:

• Per questo libro ci vogliono dieci euro. = For this book, you need ten euros.
• Per il biglietto ci vogliono cinquanta euro. = You need fifty euros for the ticket.

Because quello changes form before a noun, like some other Italian demonstratives and articles.

Before most singular masculine nouns, quello becomes quel:

• quel volo
• quel ragazzo
• quel libro

You use quello before certain sounds, for example:

• quello studente
• quello zaino
• quello psicologo

Since volo starts with a simple consonant (v), the correct form is quel volo.

Not usually in this kind of sentence. Here economico means:

• cheap
• inexpensive
• budget

So volo economico is best understood as:

• cheap flight
• budget flight

If you translated it as economic flight, that would sound unnatural in English.

Yes, absolutely. Servire can also mean to be needed.

So these are both natural:

• Ci vogliono ottanta euro.
• Ci servono ottanta euro.

The meaning is very similar: eighty euros are needed.

A small difference:

• volerci is extremely common for time, money, and effort
• servire often feels a little more directly like to be necessary / required

In everyday Italian, both are fine here.

Italian often puts the context first and the amount afterward.

This sentence is structured like this:

• Per quel volo economico = for that cheap flight
• ci vogliono = are needed / it takes
• ottanta euro = eighty euros

So literally, the structure is close to:

For that cheap flight, eighty euros are needed.

This word order is very natural in Italian. You could also hear:

• Ci vogliono ottanta euro per quel volo economico.

That means the same thing.

Because when stating an amount of money, Italian normally uses the bare number + currency noun:

• ottanta euro
• dieci euro
• un euro

You would not normally say gli ottanta euro here unless you meant some specific eighty euros already mentioned before.

So in this sentence:

• ci vogliono ottanta euro = you need eighty euros

That is the normal way to express a price or required amount.

In standard Italian, euro stays the same in both singular and plural.

So:

• un euro
• due euro
• ottanta euro

This is normal. Many currency names in Italian do change in the plural, but euro does not.

Normally, no. In this meaning, ci is part of the fixed expression volerci.

So you say:

• Ci vuole tempo
• Ci vogliono soldi
• Ci vogliono ottanta euro

If you just say vogliono ottanta euro, it would usually mean they want eighty euros, because vogliono by itself is the regular verb they want.

So ci is essential here to get the meaning are needed / it takes.