Výměna je zdarma.

Výměna is in the nominative singular. It is the subject of the sentence, so it appears in its dictionary form.

• výměna = nominative singular
• It is a feminine noun
• The ending -a is a strong clue that it belongs to a feminine noun pattern

So structurally, Výměna je zdarma works like The exchange is free.

Yes. Výměna is a feminine noun.

You can tell partly from the ending -a, which is very common for feminine nouns in Czech. Because it is feminine singular, if you later see it with adjectives, those adjectives will also have feminine singular forms, for example:

• bezplatná výměna = free exchange
• rychlá výměna = quick exchange

In your sentence, though, zdarma does not change for gender, so you do not see agreement there.

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

So:

• výměna = exchange / replacement
• je = is
• zdarma = free of charge

That gives:

• Výměna je zdarma. = The exchange is free.

Czech often uses být in the same kind of sentence where English uses to be.

Zdarma is an indeclinable word meaning free of charge, for free, or at no cost.

A useful way to think of it is that it behaves a bit like an adverb or a fixed predicative expression. The important practical point is:

• it does not change
• it does not agree with the noun in gender, number, or case

So you can say:

• Výměna je zdarma.
• Doprava je zdarma.
• Vstup je zdarma.

In all of these, zdarma stays exactly the same.

Because zdarma is not an adjective that agrees with the noun.

If it were a normal adjective, it would change depending on gender and number. But zdarma is fixed, so it stays zdarma no matter what noun is used.

Compare:

• bezplatná výměna = a free exchange
  
  • here bezplatná is an adjective, so it matches the feminine noun výměna
• Výměna je zdarma. = The exchange is free / free of charge
  
  • here zdarma does not change

Yes, but the meaning and structure are slightly different.

• Výměna je zdarma. = a full sentence: The exchange is free.
• Výměna zdarma. = more like a phrase, often used in ads, signs, headlines, or labels: Free exchange

So:

• with je = complete statement
• without je = compressed headline-style expression

Both are natural, but they are used in slightly different contexts.

Because Czech has no articles like English a / an / the.

So výměna can mean:

• an exchange
• the exchange
• sometimes just exchange as a general idea

The exact meaning depends on context.

That is why Výměna je zdarma can naturally mean:

• The exchange is free
• Exchange is free
• A replacement is free

depending on the situation.

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

The most neutral version here is:

• Výměna je zdarma.

But other orders are possible for emphasis, for example:

• Zdarma je výměna.
  This sounds more marked, emphasizing free
• Výměna zdarma
  This is a noun phrase, not a full sentence

For a learner, the safest neutral sentence is definitely:

• Výměna je zdarma.

They are very similar, and both can mean for free.

• zdarma is often felt to be a bit more neutral or standard
• zadarmo is also very common, but can sound a bit more colloquial depending on context

So you may see both:

• Výměna je zdarma.
• Výměna je zadarmo.

Both are understandable and natural, but zdarma is a very safe choice in standard written Czech.

A simple learner-friendly pronunciation guide is:

• VÝ-mně-na ye ZDAR-ma

A few helpful points:

• Czech stress is usually on the first syllable of each word
• vý is long
• je sounds like ye
• zdarma starts with a real zd cluster

Approximate IPA:

• výměna = /viːmɲɛna/
• je = /jɛ/
• zdarma = /zdarma/

You do not need perfect IPA to say it well; the main thing is first-syllable stress:

• VÝměna je ZDARma

They are related, but not identical in structure.

• Výměna je zdarma. = The exchange is free.
  This is a sentence
• Bezplatná výměna = free exchange
  This is a noun phrase

In the second one, bezplatná is a normal adjective and agrees with výměna:

• feminine
• singular
• nominative

So both are useful, but they do different jobs:

• use Výměna je zdarma for a statement
• use bezplatná výměna as a label or phrase

Yes. Depending on context, výměna can mean things like:

• exchange
• replacement
• swap
• changeover

So Výměna je zdarma might be used in different real-life situations, for example:

• a store allowing a size exchange
• a company replacing a defective item
• a service changing a part at no cost

The exact English translation depends on context, even though the Czech sentence stays the same.