Tento prostředek je levný.

Czech does not normally use articles.

So Tento prostředek je levný can still mean something like This remedy/device/means is cheap, even though there is no separate word for the.

Czech usually shows definiteness through:

• context
• word order
• demonstratives such as ten or tento

Here, tento already makes the noun definite and specific: this ...

Tento means this.

It is the masculine singular nominative form of the demonstrative tento.

A useful rough distinction is:

• tento = this (more explicit)
• ten = often that, but in everyday Czech it can also function more loosely, sometimes almost like the depending on context

So tento prostředek is a clear, straightforward way to say this средство/means/remedy/device.

In everyday speech, you may also hear:

• ten prostředek
• tenhle prostředek

But tento prostředek is perfectly correct and clear.

Prostředek is masculine inanimate.

That matters because words around it must agree with it:

• tento is the masculine singular nominative form
• levný is also the masculine singular nominative form

So the sentence matches grammatically:

• tento prostředek
• je levný

If the noun had a different gender, these forms would change. For example:

• ta věc je levná = that/this thing is cheap
• to auto je levné = that/this car is cheap

It is in the nominative case.

Why? Because it is the subject of the sentence — the thing being talked about.

In Tento prostředek je levný:

• tento prostředek = the subject
• je levný = what is being said about the subject

So the basic structure is:

• [subject in nominative] + [form of být] + [predicate adjective]

Because levný has to agree with prostředek.

Here it is:

• masculine
• singular
• nominative

That gives the form levný.

Compare:

• masculine singular: levný prostředek
• feminine singular: levná věc
• neuter singular: levné auto
• plural: levné prostředky

So the ending -ý is not random; it shows grammatical agreement.

Because the subject is singular, and it is masculine inanimate.

So:

• je = is (3rd person singular of být)
• levný = singular masculine form of the adjective

If the subject were plural, you would use:

• jsou levné = are cheap

For example:

• Tyto prostředky jsou levné. = These means/remedies/products are cheap.

In a normal sentence like this, yes, je is necessary.

Czech does sometimes omit forms of být in special styles, such as:

• headlines
• notes
• very informal shorthand
• some literary effects

But in ordinary standard speech and writing, you say:

• Tento prostředek je levný.

So for learners, the safe rule is:

• in present-tense sentences like X is Y, keep je

A learner-friendly guide:

• Tento ≈ TEN-to
• prostředek ≈ PRO-stře-dek
• levný ≈ LEV-nee

A few important points:

1. Stress

   • Czech stress is normally on the first syllable
   • so: TEN-to, PRO-stře-dek, LEV-ný

2. ý

   • ý is a long vowel
   • in modern pronunciation, y and i sound the same, but ý is long
   • so levný sounds roughly like LEV-nee, with a long final vowel

3. ř

   • the ř in prostředek is famously difficult
   • for beginners, an approximation somewhere between r and zh is fine
   • you do not need to master it immediately to be understood

Yes — prostředek is a broad word, and its exact meaning depends on context.

It can mean things like:

• means
• method
• agent
• remedy
• product
• device

For example:

• dopravní prostředek = means of transport / vehicle
• čisticí prostředek = cleaning product/agent
• léčebný prostředek = remedy / medicinal means

So even if the meaning has already been supplied to you, it is good to know that prostředek is a flexible Czech word.

The given order is the most neutral one:

• Tento prostředek je levný.

But Czech word order is fairly flexible, and changing it often changes emphasis rather than basic meaning.

Possible alternatives include:

• Prostředek je levný. = The means/product/remedy is cheap.
• Levný je tento prostředek. = It is this means/product that is cheap.
• Je tento prostředek levný? = Is this means/product cheap?

So the original version is a good default sentence, but it is not the only possible order.

In the plural, several words change:

• Tento prostředek je levný.
• Tyto prostředky jsou levné.

Changes:

• tento → tyto
• prostředek → prostředky
• je → jsou
• levný → levné

This shows how strongly Czech grammar depends on number and agreement.

You would change the demonstrative and the adjective to match the noun.

Examples:

• masculine inanimate: Tento prostředek je levný.
• feminine: Tato věc je levná.
• neuter: Toto auto je levné.

So when learning Czech, it helps to memorize nouns together with their gender, because that affects the forms of other words in the sentence.