Learn Hardcore German: Meine Mutter ist sehr sparsam und kauft Brot nur im Angebot. - My mother is very thrifty and buys bread only when it is on sale.

Here Meine Mutter is the subject of the sentence, so it’s in the nominative case, feminine singular.
The correct form of mein in nominative feminine is meine – hence Meine Mutter.

Why is Brot written without any article (not das Brot or ein Brot)?

German often drops the article when talking about something in a general or uncountable sense, especially with food and drink.

Sie kauft Brot. = She buys bread (in general, some bread).
Sie kauft das Brot. = She buys the bread (a specific bread already known).
Sie kauft ein Brot. = She buys a loaf of bread / one bread.

In your sentence, Brot means “bread in general”, so no article is needed.

What exactly does sparsam mean? Is it like “stingy”?

Sparsam means thrifty, economical, careful with money.
It is usually positive or neutral, suggesting sensible saving.

“Stingy” would be geizig, which has a negative feeling: someone who doesn’t want to spend at all, even when it would be reasonable.

So:

sparsam = thrifty
geizig = stingy

Why is it ist sehr sparsam and not something like hat Sparsamkeit?

German, like English, usually uses “to be” with adjectives describing character or state:

Meine Mutter ist sehr sparsam. = My mother is very thrifty.

You can make a noun (Sparsamkeit = thrift), but that’s less natural here:

Sie hat große Sparsamkeit. – grammatically possible but sounds odd in everyday speech.

Using sein + Adjektiv (ist sparsam) is the normal pattern.

Why is Brot capitalized?

In German, all nouns are capitalized, no matter where they appear in the sentence:

das Brot
ein Angebot
die Mutter

So Brot and Angebot must start with a capital letter.

What does nur im Angebot mean exactly?

Nur im Angebot literally means “only in the offer”, but idiomatically it means:

only when it’s on sale / only when it’s on special offer / only when discounted

Im is the contraction of in dem (“in the”).
Angebot here refers to a special offer / sale price, not just “an offer” in the abstract sense.

Why is it im Angebot and not in Angebot?

The preposition in with a location usually takes the dative case.
Angebot is a neuter noun (das Angebot), so dative singular is dem Angebot.

In dem Angebot contracts to im Angebot:

in dem Angebot → im Angebot

You cannot say in Angebot here; that would be incorrect in standard German.

Could you explain the word order in kauft Brot nur im Angebot? Why is kauft in that position?

German main clauses follow the verb-second (V2) rule: the finite verb (here kauft) must be in second position in the clause.

The second clause is:

(Sie) kauft Brot nur im Angebot.

The (understood) subject sie is first, the verb kauft is second.
Everything else (Brot nur im Angebot) comes after the verb. That’s why you can’t move kauft to the end in a normal main clause.

What is the difference between kauft Brot nur im Angebot and kauft nur Brot im Angebot?

The position of nur changes what is being restricted:

kauft Brot nur im Angebot
→ She buys bread only when it’s on sale (she doesn’t buy bread at full price).
kauft nur Brot im Angebot
→ She buys only bread when it’s on sale (and no other products on sale).

In your sentence, the intended meaning is that the condition “on sale” applies to bread, not that bread is the only discounted thing she buys.

Why is there no sie before kauft in the second part?

The subject Meine Mutter applies to both parts of the sentence. In German (and English) you don’t have to repeat the subject if it’s the same:

Meine Mutter ist sehr sparsam und (sie) kauft Brot nur im Angebot.

Adding sie is grammatically possible but usually unnecessary and stylistically less smooth. The shared subject is understood.

Why is it sehr sparsam and not viel sparsam?

In German:

sehr is used to intensify adjectives and adverbs
- sehr sparsam = very thrifty
- sehr schnell = very fast
viel is used mostly with verbs and uncountable nouns
- Sie spart viel. = She saves a lot.
- Sie hat viel Geld. = She has a lot of money.

So with an adjective like sparsam, you normally use sehr, not viel.

Can I say im Sonderangebot instead of im Angebot?

Yes:

im Angebot = on sale / in the (special) offer
im Sonderangebot = in the special offer, explicitly “special sale offer”

Im Angebot is more general and very common in everyday speech and supermarket contexts.
Im Sonderangebot makes it more explicit that it’s some special promotional price, but in many contexts they overlap.

Is there an implied “es ist” after im Angebot? As in nur, wenn es im Angebot ist?

Conceptually, yes. The full idea is:

… und kauft Brot nur, wenn es im Angebot ist.
= and only buys bread when it is on sale.

German often leaves out parts that are clear from context.
In your sentence, nur im Angebot is a shortened, more fluent way to express the same condition.

What case is Angebot in, and why?

Angebot here is in the dative singular.

Reason:

The preposition in with a static situation (no movement into something) usually takes the dative case.
das Angebot (nominative) → dem Angebot (dative).

Then in dem Angebot contracts to im Angebot.