Cena po dogovoru je u opisu.

Po dogovoru is a common Serbian expression meaning by agreement, as agreed, or more naturally in ads, negotiable.

So cena po dogovoru means:

• price by agreement
• price to be agreed
• negotiable price

In sales ads, it usually means the seller and buyer will agree on the final price later.

Because the preposition po often requires the locative case in this kind of expression.

• base form: dogovor = agreement
• locative singular: dogovoru

So:

• po dogovoru = by agreement / as agreed

This is something learners often just have to get used to as a fixed pattern:

• po planu = according to plan
• po zakonu = according to the law
• po dogovoru = by agreement

Opisu is also in the locative singular.

The noun is:

• opis = description

After u when it means in a place/location, Serbian uses the locative:

• u opisu = in the description

So:

• opis → dictionary form
• u opisu → locative form

Because after u meaning in, Serbian normally uses the locative case for location.

Compare:

• opis = description
• u opisu = in the description

This is the same pattern as:

• u gradu = in the city
• u kući = in the house
• u tekstu = in the text

If u indicates movement into something, Serbian usually uses the accusative instead. But here there is no movement, only location.

Je is the 3rd person singular of biti = to be.

Here it links the subject and the location:

• Cena po dogovoru = the negotiable price / the price by agreement
• je = is
• u opisu = in the description

So the structure is basically:

• The price by agreement is in the description.

In Serbian, forms of to be are often omitted in some contexts, but in a normal sentence like this, je is expected.

Yes, very much so. In ads and marketplaces, cena po dogovoru is a very common phrase.

It functions almost like a label:

• Cena po dogovoru. = Price negotiable.

So even though you can analyze it word by word, many native speakers process it as a ready-made advertising phrase.

It is understandable, but depending on the context, a native speaker might choose a slightly different wording.

For example:

• Cena je u opisu. = The price is in the description.
• Cena po dogovoru. = Price negotiable.

Putting them together as Cena po dogovoru je u opisu is grammatically understandable, but it may sound a little unusual unless the description explains that the price is negotiable or gives pricing details.

So the sentence is not wrong, but it feels somewhat like ad language rather than polished standard prose.

Yes. Serbian word order is more flexible than English word order.

This sentence could be rearranged, for example:

• U opisu je cena po dogovoru.

That would still be understandable, but it changes the emphasis.
The original sentence starts with cena po dogovoru, so that idea is foregrounded first.

In short:

• Cena po dogovoru je u opisu. = neutral, starting with the topic of price
• U opisu je cena po dogovoru. = emphasizes where the information is

Because Serbian does not have articles like English a/an/the.

So cena can mean:

• a price
• the price

The exact meaning depends on context.

In this sentence, English would usually translate it with the:

• The price is in the description or
• The negotiable price is in the description

But Serbian does not need a separate word for that.

The structure is:

• Cena po dogovoru = subject noun phrase
• je = verb
• u opisu = location phrase

Word by word:

• cena = price
• po dogovoru = by agreement / negotiable
• je = is
• u opisu = in the description

So grammatically it is a simple copular sentence:
subject + to be + location

Not always. A literal translation is useful for understanding the grammar, but in real English it often sounds more natural as:

• negotiable
• to be agreed
• as agreed

In ads, cena po dogovoru is almost always best understood as:

• price negotiable

So the literal meaning and the natural meaning are slightly different, and that is very common in set phrases.