Цена не столь высокая.

Столь means so, that, or to such a degree. In this sentence, не столь высокая means not so high / not that high.

It is close to:

• не такая высокая
• не настолько высокая

So Цена не столь высокая is a fairly compact way to say The price is not that high.

In Russian, the verb to be is usually omitted in the present tense.

So:

• Цена высокая. = The price is high.
• Цена не столь высокая. = The price is not that high.

Russian does not normally say Цена есть высокая here. That would sound unnatural.

In the past or future, you would use forms of быть:

• Цена была высокой. = The price was high.
• Цена будет высокой. = The price will be high.

Because цена is a feminine noun, and adjectives must agree with the noun they describe in gender, number, and case.

Here:

• цена = feminine singular
• высокая = feminine singular form of высокий

Compare:

• высокий стол = a tall/high table
• высокая цена = a high price
• высокое здание = a tall building
• высокие цены = high prices

Russian has two adjective forms here:

• long form: высокая
• short form: высока

Both can be used in predicate position, but they are not used in exactly the same way.

In this sentence, высокая sounds natural because the pattern is:

• не столь + long-form adjective

So:

• Цена не столь высокая. = natural
• Цена не так высока. = also natural, but with a different structure

Notice the matching patterns:

• не столь высокая
• не так высока

So the issue is not just long vs short adjective, but also which intensifier goes with which structure.

It is nominative singular feminine.

Even though высокая comes after the noun and acts like part of the predicate, it is still in the nominative here:

• Цена высокая.
• Цена не столь высокая.

This is a common pattern in Russian with present-tense sentences where the verb to be is omitted.

They are similar, but not identical.

• невысокая = not high / low-ish / fairly low
• не столь высокая = not so high / not that high

The second one is more relative. It usually implies a comparison, stated or unstated:

• not as high as expected
• not as high as another price
• not as high as someone says

So:

• Цена невысокая. = The price is low / not high.
• Цена не столь высокая. = The price is not that high.

Yes, absolutely. Цена не такая высокая is very common and natural.

These are close:

• Цена не столь высокая.
• Цена не такая высокая.
• Цена не настолько высокая.

The differences are mostly in style and nuance:

• не такая высокая = very common, neutral, conversational
• не настолько высокая = emphasizes degree more strongly
• не столь высокая = a bit more formal or literary

So a learner will probably hear не такая высокая more often in everyday speech.

Yes, столь tends to sound a bit more formal, bookish, or written than так or такой.

Compare:

• Цена не такая высокая. = everyday, neutral
• Цена не столь высокая. = slightly more formal
• Цена не настолько высокая. = also natural, often used when stressing degree

That does not mean столь is wrong or rare—it is perfectly normal—but it is less colloquial than some alternatives.

Because Russian also uses the adjective высокий with price:

• высокая цена = high price
• низкая цена = low price

So this part works very much like English:

• high prices = высокие цены
• low prices = низкие цены

For an English speaker, this is one of the easier collocations to remember.

No, Russian word order is fairly flexible, but changing it affects emphasis and style.

Neutral order:

• Цена не столь высокая.

You could also see:

• Не столь высокая цена. = Not such a high price / A price that is not so high
• Цена столь не высокая = generally not the normal way to say it

So for a simple statement, Цена не столь высокая is the best model to follow.

Yes. That is very common.

Не столь высокая often suggests an implicit comparison:

• not as high as expected
• not as high as before
• not as high as in another store
• not as high as someone feared

Russian often leaves that comparison unstated when it is clear from context.

So the sentence can feel slightly more nuanced than a plain The price is not high. It often means The price is not as high as you might think.