i manhwaneun pumjeoriraseo oneureun sal su eobseoyo.

Here, 이 만화는 makes this comic the topic of the whole sentence: as for this comic...

Korean often uses 은/는 when introducing what the sentence is about, even if that noun would be the object of a verb in English. In this sentence, this comic is both:

• the thing that is sold out
• the thing the speaker wants to buy

So 는 is very natural here.

품절 is basically a noun meaning sold-out status or being sold out.

That is why Korean does not treat it like a normal descriptive verb such as 비싸다 or 좋다. Instead, it combines with 이다:

• 품절이다 = to be sold out

Because 품절 is a noun, Korean needs the copula 이다 before adding the reason ending.

So the structure is:

• 품절이다 = is sold out
• 품절이라서 = because it is sold out

If you said 품절해서, it would sound wrong because 품절 is not a verb by itself here.

-이라서 means because it is... or since it is... when attached to a noun + 이다.

So:

• 품절이라서 = because it is sold out

It connects the reason to the result:

• reason: it is sold out
• result: I can’t buy it today

That 는 also marks a topic or adds contrast.

오늘은 can feel like:

• as for today
• today, at least
• today though

So the sentence can suggest something like: I can’t buy it today—maybe tomorrow or when it is restocked, but not today.

This is the pattern:

• verb stem + -(으)ㄹ 수 있다 = can do
• verb stem + -(으)ㄹ 수 없다 = cannot do

So:

• 사다 = to buy
• 살 수 있다 = can buy
• 살 수 없다 = cannot buy
• 살 수 없어요 = cannot buy, in polite speech

Literally, 수 means something like way/method/possibility, so 살 수 없어요 is there is no possibility/way to buy it.

Because this grammar uses the form -(으)ㄹ before 수 있다/없다.

With 사다, you remove -다 and attach -ㄹ:

• 사-
• 사 + ㄹ
• 살

So:

• 사다 → 살 수 없다

This is not a special irregular verb here; it is just how this pattern is formed.

Yes. 못 사요 is very natural and common in conversation.

Compare:

• 살 수 없어요 = cannot buy it / am not able to buy it
• 못 사요 = can’t buy it

In everyday speech, 못 사요 often sounds a little more casual and direct. 살 수 없어요 can sound slightly more explicit or formal.

The subject is not stated, but it is usually understood from context.

Most naturally, it means:

• I can’t buy it today

But Korean often leaves out subjects when they are obvious. Depending on context, it could also mean something more general like:

• it can’t be bought today

Korean often uses the present form to describe a current situation that affects what is possible now or later today.

So 살 수 없어요 means:

• it is not possible to buy it
• therefore I can’t buy it today

Korean does not need a special future form here.

만화 most often means a comic or comic book, and it can also refer to manga in many contexts.

Depending on the situation, it can sometimes be translated as cartoon, but if you specifically mean an animated cartoon, Korean more often uses words like:

• 애니메이션
• 만화영화

So in this sentence, comic is a very natural translation.

Yes. Both are correct.

For example:

• 품절이라서 오늘은 살 수 없어요
• 품절이어서 오늘은 살 수 없어요

The meaning is basically the same: because it is sold out.
-이라서/-라서 is very common and natural in speech, while -이어서/여서 can sound a little more careful or slightly more formal depending on context.

-어요 is the standard polite speech style.

So 없어요 is the polite form of 없다. It is appropriate for everyday conversation when you want to sound respectful but not overly formal.

Compare:

• 없다 = plain dictionary/plain style
• 없어요 = polite
• 없습니다 = formal polite