In der Rechnungskorrektur steht ein niedriger Grundpreis.

Because in is a two-way preposition in German: it can take either the dative or the accusative.

• Dative is used for a location: where something is
• Accusative is used for direction/movement: where something is going

Here, the sentence describes where the information appears, so it is a location:

• in der Rechnungskorrektur = in the bill correction / on the corrected invoice

So der is the dative feminine form of die Rechnungskorrektur.

Yes, stehen literally means to stand, but it is also very commonly used for written information.

In this kind of sentence, stehen means something like:

• to be written
• to appear
• to say
• to be stated

So In der Rechnungskorrektur steht ... means that this information is written in the billing correction document.

This is very natural German. Similar examples:

• Im Brief steht, dass ... = The letter says that ...
• Auf dem Schild steht ... = The sign says ...

German main clauses follow the verb-second rule, not a fixed English-style subject-first rule.

The first position in the sentence can be taken by many different elements. Here, the sentence begins with the prepositional phrase:

• In der Rechnungskorrektur

That counts as position 1. The finite verb must then come in position 2:

• steht

After that comes the subject:

• ein niedriger Grundpreis

So the structure is:

• In der Rechnungskorrektur | steht | ein niedriger Grundpreis

If you put the subject first, you could also say:

• Ein niedriger Grundpreis steht in der Rechnungskorrektur.

That is grammatically possible, though the original version sounds more natural if you want to focus first on where the information appears.

Because Grundpreis is masculine singular and it is the subject of the sentence, so it is in the nominative case.

The noun phrase is:

• ein niedriger Grundpreis

After ein with a masculine nominative singular noun, the adjective takes the ending -er.

So:

• ein niedriger Grundpreis = correct

Compare:

• ein niedriger Preis = masculine nominative
• einen niedrigen Preis = masculine accusative
• eine niedrige Gebühr = feminine nominative/accusative

This is an example of mixed adjective declension.

Rechnungskorrektur is feminine: die Rechnungskorrektur.

In German compounds, the last part determines the grammatical gender. Here the last part is:

• Korrektur = correction

And die Korrektur is feminine, so the whole compound is feminine too:

• die Rechnungskorrektur

That is why the sentence has:

• in der Rechnungskorrektur
  because der is the dative feminine form.

German often combines nouns into one longer noun. Here:

• Rechnung = bill / invoice
• Korrektur = correction

Together:

• Rechnungskorrektur = invoice correction / bill correction

The first part narrows the meaning of the second part. So this is a correction relating to a bill/invoice.

A useful rule: in German compounds, the main word is the last one, and the earlier part describes it.

So this is a kind of Korrektur, specifically one connected with a Rechnung.

Because Rechnung is not acting as a separate noun phrase here. It is part of a compound noun.

In German compounds, the first noun usually appears in a basic stem form, without its own article:

• die Rechnung
• die Korrektur
• die Rechnungskorrektur

So you do not say:

• die Rechnung die Korrektur

Instead, the two nouns combine into one word.

This is very common in German:

• Haus + Tür = Haustür
• Sommer + Urlaub = Sommerurlaub
• Preis + Liste = Preisliste

Grundpreis means the base price, basic price, or basic charge, depending on context.

It usually refers to a fixed amount before additional costs, usage charges, or other components are added.

In billing or contract contexts, it often means:

• the regular base fee
• the standard monthly charge
• the fixed starting price

So in this sentence, the document states that the base charge is low or lower than expected.

Not exactly. Niedrig means low, not cheap.

So ein niedriger Grundpreis means:

• a low base price
• a low basic charge

If you wanted to say cheap, German often uses words like:

• billig
• günstig

But those words focus more on affordability or good value. Niedrig is more neutral and often used for numbers, rates, levels, fees, and prices in a factual way.

So niedriger Grundpreis sounds especially natural in administrative, financial, or technical contexts.

Because the subject is singular:

• ein niedriger Grundpreis

The finite verb agrees with the subject in number and person. Since Grundpreis is singular, the verb is singular too:

• steht = third person singular

If the subject were plural, the verb would be plural:

• In der Rechnungskorrektur stehen mehrere niedrige Grundpreise.

Usually, steht is better here.

• steht focuses on what is written in the document
• ist would sound less idiomatic in this context

German often uses stehen for text and printed information:

• In dem Vertrag steht ...
• Auf der Rechnung steht ...
• In der E-Mail steht ...

So while ist may sometimes be understandable in other structures, steht is the natural verb when talking about information appearing in writing.

Because in German, all nouns are capitalized.

In this sentence, the nouns are:

• Rechnungskorrektur
• Grundpreis

Adjectives like niedriger are not capitalized here, because they are just describing the noun.

This is one of the most noticeable spelling differences between German and English.