De prijs is negentig euro.

Because prijs is a de-word in Dutch. Dutch nouns take either de or het, and you mostly have to learn that with each noun.

• de prijs = the price
• not: het prijs

There is no simple rule that always tells you which article to use, so it is best to memorize prijs together with de.

This is the normal Dutch word order for a main clause:

subject + verb + rest

So here:

• De prijs = subject
• is = verb
• negentig euro = complement

Dutch main clauses usually put the finite verb in the second position. That is why is comes right after De prijs.

Is is the third-person singular form of zijn (to be).

Since the subject is de prijs (the price), Dutch uses:

• de prijs is ...
• not: de prijs ben ...
• not: de prijs zijn ...

So is matches the singular subject prijs.

Because negentig euro is an amount, and amounts normally appear without an article here.

So Dutch says:

• De prijs is negentig euro.

not:

• De prijs is een negentig euro.

That would sound wrong. In this sentence, negentig euro works as the stated price amount.

When Dutch gives a price or amount of money, it very often uses the currency name without the plural ending after a number:

• tien euro
• vijftig euro
• negentig euro

You may also see euro's in other contexts, especially when talking about separate coins, notes, or units more generally, but in simple price statements negentig euro is very natural and standard.

So in this sentence, negentig euro is exactly what you would expect.

Prijs is pronounced roughly like price in English, but not exactly.

A few points:

• pr- is similar to English pr
• ij is a Dutch vowel sound often written in learner materials as something a bit like the vowel in eye, though the exact sound is different
• s is just s

A rough English approximation is price, but remember that the Dutch ij has its own sound.

A rough pronunciation guide is something like NAY-ghen-tikh or NEH-ghen-tikh, depending on accent and how detailed you want to be.

Important points:

• negen means nine
• -tig is the ending used for numbers like twintig, dertig, veertig, vijftig, etc.
• the g in standard Dutch is usually a harsh throat sound, not like the English g in go

If you are a beginner, it is fine to aim for a simpler version first and improve the g sound over time.

In Dutch, euro is usually pronounced approximately YUR-oh, though the exact vowel quality is Dutch, not English.

The first part, eu, is a common Dutch vowel combination, and learners often need some practice with it. A rough approximation is acceptable at first, but it is worth listening to native audio because this sound does not match a single standard English vowel perfectly.

Because Dutch number words like this are normally written as single words.

So:

• negentig = ninety

This is completely normal in Dutch. You do not split it into separate parts in standard spelling.

No. A very common alternative is:

• Het kost negentig euro. = It costs ninety euros.

The difference is mainly in focus:

• De prijs is negentig euro. focuses on the price
• Het kost negentig euro. focuses on what something costs

Both are natural, but the sentence you have is perfectly correct.

Yes. Bedraagt comes from bedragen, which is often used in formal or written Dutch for amounts.

So you may see:

• De prijs is negentig euro. — neutral, everyday
• De prijs bedraagt negentig euro. — more formal

For everyday conversation, is is simpler and very common.

Because negentig is a numeral, and in this kind of sentence it stays the same. Dutch numbers do not change here for gender or case.

So you simply say:

• negentig euro
• negentig boeken
• negentig huizen

The form negentig stays the same.

It is the predicative complement after is. In other words, it tells you what the price is.

Structure:

• De prijs = subject
• is = linking verb
• negentig euro = complement describing the subject

This is similar to sentences like:

• Jan is dokter.
• Het antwoord is nee.
• De prijs is negentig euro.

Yes, but if you move another element to the front, the verb still has to stay in the second position.

For example:

• Vandaag is de prijs negentig euro.

Here:

• Vandaag is first
• is is still second
• de prijs comes after the verb

That verb-second pattern is a very important Dutch rule in main clauses.

It is singular.

• de prijs = the price
• de prijzen = the prices

Because the subject is singular, the verb is also singular:

• De prijs is ...
• De prijzen zijn ...

So if you changed it to plural, you would say:

• De prijzen zijn negentig euro.

Dutch handles currency names a bit differently in amount expressions. In a plain price statement, Dutch commonly says:

• negentig euro

where English says:

• ninety euros

So this is one of those places where you should not translate word-for-word from English. The Dutch amount expression has its own pattern, and negentig euro is the normal form to learn.