Zhèjiā wǎngdiàn de jiàgé bú guì, kěshì zhìliàng bú tài hǎo.

家 is the measure word for businesses and establishments such as stores, restaurants, companies, and hotels.

So:

• 这家网店 = this online shop
• literally: this + measure word for shop/business + online store

You cannot usually say 这网店 in standard Mandarin when pointing out one specific shop. The measure word is expected.

Other examples:

• 这家饭店 = this restaurant
• 那家公司 = that company

Yes, 网店 is a common two-syllable noun meaning online store/shop.

It is made up of:

• 网 = internet / net
• 店 = shop / store

So 网店 literally means internet shop.

It behaves like a normal noun in the sentence:

• 这家网店 = this online shop
• 网店的价格 = the online shop’s prices

Here, 的 links a modifying noun to another noun. It works a lot like ’s or of in English.

• 网店的价格 = the online shop’s prices / the prices of the online shop

Structure:

• A 的 B = B of A / A’s B

So here:

• 网店 = online shop
• 价格 = price
• 网店的价格 = the shop’s prices

This is a very common pattern in Chinese.

This is because of a very common tone change rule.

Normally:

• 不 is fourth tone: bù

But when 不 comes before another fourth-tone syllable, it changes to second tone:

• 不贵 → bú guì
• 不好 → bú hǎo? No—here 好 is third tone, so normally 不 stays bù
• But in this sentence it is written 不太好 as bú tài hǎo because 不 comes before 太, and 太 is fourth tone

So:

• 不贵 → bú guì
• 不太好 → bú tài hǎo

This change is about pronunciation, not meaning.

不贵 means not expensive, which is a bit more neutral than very cheap.

Compare:

• 不贵 = not expensive
• 很便宜 = very cheap

A speaker may choose 不贵 when they want to sound more balanced or less strong. In this sentence, that fits well because the speaker is giving both a positive point and a negative point:

• the price is not expensive
• but the quality is not very good

So 不贵 sounds natural and measured.

Yes, 但是 could also work here. Both 可是 and 但是 mean but.

• 可是 often sounds a little more conversational or emphatic
• 但是 is also very common and can sound slightly more neutral or formal depending on context

So this sentence could also be:

• 这家网店的价格不贵，但是质量不太好。

Both are natural.

Not exactly.

• 质量不好 = the quality is not good
• 质量不太好 = the quality is not very good

Adding 太 makes the statement a little softer and less direct. It often sounds more natural in conversation when giving criticism.

So:

• 不好 = stronger, more direct
• 不太好 = softer, more moderate

In this sentence, 不太好 suggests the quality is somewhat disappointing, but the speaker is not making the harshest possible criticism.

不太 + adjective is a very common pattern meaning not very + adjective.

Examples:

• 不太好 = not very good
• 不太贵 = not very expensive
• 不太方便 = not very convenient
• 不太喜欢 = don’t really like

It often softens what you are saying and can sound more polite or less blunt than a plain negative.

So in this sentence:

• 质量不太好 = the quality is not very good

Because 贵 and 好 are adjectives, and in Chinese adjectives can often act as the predicate directly.

So Chinese says:

• 价格不贵
• 质量不太好

You do not need 是 the way English uses is.

Incorrect patterns would be:

• 价格是不贵 ❌
• 质量是不太好 ❌

Use 是 mainly when linking nouns, not ordinary adjectives in this kind of sentence.

For example:

• 他是老师。 = He is a teacher.
• 他很忙。 = He is busy.

Because the adjective is already being negated by 不.

In an affirmative statement, Chinese often uses 很 before an adjective:

• 价格很贵。 = The price is expensive.

But with negation, 不 does the job:

• 价格不贵。 = The price is not expensive.

So you do not need 很 there.

Compare:

• 贵 by itself can sound contrastive or incomplete in some contexts
• 很贵 is a normal affirmative statement
• 不贵 is a normal negative statement

The structure is:

• 这家网店的价格不贵，可是质量不太好。

You can think of it as:

• [Topic/possessor] + 的 + [noun] + adjective
• then a contrast
• then another noun + adjective phrase

More specifically:

• 这家网店的价格 = this online shop’s prices
• 不贵 = are not expensive
• 可是 = but
• 质量 = quality
• 不太好 = is not very good

So the overall pattern is basically:

• This shop’s prices are not expensive, but the quality is not very good.

Yes, that is grammatically possible:

• 这家网店的价格不贵，可是它的质量不太好。

But in Chinese, once the topic is clear, speakers often omit repeated words like 它的 if they are obvious from context.

So the original version sounds more natural and less repetitive:

• 这家网店的价格不贵，可是质量不太好。

This kind of omission is very common in Chinese.

Yes, 价钱 could be used here too in many contexts.

• 价格 is a bit more formal or neutral
• 价钱 can sound a little more conversational

So:

• 这家网店的价格不贵。
• 这家网店的价钱不贵。

Both are understandable and natural, though 价格 fits slightly better in a general descriptive statement like this.

质量 means quality, and it is used very broadly.

It can refer to:

• product quality
• service quality
• construction quality
• sound quality
• work quality

In this sentence, it most naturally refers to the quality of the products sold by the online shop.

So even though the sentence talks about the shop, 质量 usually points to what the shop is offering, not the abstract existence of the shop itself.