Fatura doksan lira.

In Turkish, the verb to be is often left out in the present tense when you are making a simple statement.

So:

• Fatura doksan lira. = The bill is ninety lira.

This is completely normal Turkish.
English needs is, but Turkish usually does not in this kind of sentence.

If you want a more formal or emphatic version, you can say:

• Fatura doksan liradır.

Here, -dır adds a more formal is sense, but in everyday speech it is often omitted.

This is a very natural Turkish sentence order for a simple equational statement:

• Fatura = the bill
• doksan lira = ninety lira

So the structure is basically:

• [subject] + [predicate]

That gives:

• Fatura doksan lira.
• literally: The bill ninety lira.

Turkish often puts the thing being talked about first, then gives the information about it.

After numbers in Turkish, the noun usually stays singular, not plural.

So you say:

• doksan lira = ninety lira
• üç kitap = three books
• beş kişi = five people

This is different from English, where we say ninety liras only rarely and usually ninety lira in currency contexts, but with regular count nouns we say three books. In Turkish, the singular form after a number is the normal rule.

It can mean bill or invoice, depending on context.

Common uses:

• a restaurant or hotel bill
• a utility bill
• an invoice

So Fatura doksan lira could mean:

• The bill is ninety lira.
• The invoice is ninety lira.

The exact English word depends on the situation.

Turkish does not have a separate word like English the.

A bare noun like fatura can mean:

• the bill
• a bill

The context tells you which one is meant.

In a sentence like Fatura doksan lira, it will often be understood as the bill is ninety lira, because you are usually talking about a specific bill already known in the conversation.

A simple pronunciation guide:

• fatura ≈ fa-too-RAH
• doksan ≈ doke-SAHN
• lira ≈ lee-RAH

A few helpful points:

• Turkish r is usually lightly rolled or tapped.
• Turkish vowels are pronounced clearly and consistently.
• Stress is often near the end, though actual sentence rhythm can vary.

A rough full pronunciation:

• fa-too-RAH doke-SAHN lee-RAH

Yes. That is grammatical.

• Fatura doksan lira. = normal, everyday, natural
• Fatura doksan liradır. = more formal, more definite, sometimes more explanatory

The ending -dır is a copular ending that can sound:

• formal
• official
• explanatory
• emphatic

In ordinary conversation, people very often prefer the shorter version:

• Fatura doksan lira.

Doksan lira is the predicate: it tells you what the bill amounts to.

Breakdown:

• doksan = ninety
• lira = lira

Together:

• doksan lira = ninety lira

So the sentence is identifying the bill with that amount:

• The bill = ninety lira

No. Fatura is in the basic form (often called the nominative form).

There is no case ending on it here.

Compare:

• fatura = the bill / a bill
• faturayı = the bill (as a direct object)
• faturaya = to the bill
• faturada = on the bill / in the bill
• faturadan = from the bill

In Fatura doksan lira, the noun just appears in its plain dictionary form.

You can, but the basic version is the most natural in a neutral context:

• Fatura doksan lira.

Other word orders may be possible for emphasis, but they sound more marked and depend on context.

For a learner, the safest and most natural version is:

• Fatura doksan lira.

Because this is just a simple amount expression used as the predicate.

• doksan already means ninety
• lira is the unit of currency

No extra ending is needed here.

If the sentence were in a different grammatical environment, you might see suffixes, for example:

• Fatura doksan lirayı geçti. = The bill exceeded ninety lira.
• Fatura doksan liraya çıktı. = The bill went up to ninety lira.

But in Fatura doksan lira, the bare form is exactly what you want.

Yes. It is short, natural, and very common-style Turkish.

In speech, Turkish often prefers concise sentences like this:

• Toplam elli lira. = The total is fifty lira.
• Bilet yüz lira. = The ticket is one hundred lira.
• Fatura doksan lira. = The bill is ninety lira.

So this sentence sounds perfectly normal in everyday use.