oneureun uni eobseoseo ipjanggwoneul mos sasseo.

I had no luck today, so I could not buy an admission ticket.

Breakdown of oneureun uni eobseoseo ipjanggwoneul mos sasseo.

• 사다: to buy
• 오늘: today
• 없다: to not have
• 못: not

Questions & Answers about oneureun uni eobseoseo ipjanggwoneul mos sasseo.

Why does 오늘 take -은 in 오늘은?

-은/는 is the topic particle. In 오늘은, it marks today as the topic, with a slight sense of as for today or today, at least.

So 오늘은 운이 없어서... can feel a bit like:

• As for today, I had bad luck, so...
• Today, I was unlucky, so...

Using 오늘이 instead would sound different, because -이/가 marks the grammatical subject rather than the topic.

Why is it 운이 없어서 and not 운은 없어서?

In the expression 운이 없다, 운 is treated as the subject of 없다, so -이/가 is natural.

• 운이 없다 = to have no luck / to be unlucky

This is a very common fixed expression.
Using 운은 없다 is possible in some contrastive contexts, but it is not the default form here.

For example:

• 실력은 있는데 운은 없어. = He has skill, but he has no luck.

In your sentence, 운이 없어서 is the normal, natural choice.

What exactly does 운이 없다 mean? Is it literally there is no luck?