deungrokgeumeul naeneura ibeon dareneun yeohaeng gyehoegeul mos sewosseo.

등록금 means tuition or tuition fee.
The -을 is the object particle, so 등록금을 내다 means to pay tuition.

A few related points:

• 등록금 = tuition / school fees
• 내다 = to pay
• So 등록금을 내다 is a very common expression for paying tuition

내느라 comes from 내다 + -느라.

The grammar -느라 means something like:

• because I was busy doing...
• as a result of spending time/effort doing...
• and usually the second clause is negative or describes an unfortunate result

So:

• 등록금을 내느라 = because I was busy paying tuition = because paying tuition took my time/money/energy

In this sentence, the bad result is:

• 이번 달에는 여행 계획을 못 세웠어 = I couldn’t make travel plans this month

A very important point: with -느라, the subject is normally the same in both parts.
So the person who paid the tuition is also the person who couldn’t make the travel plans.

They can both sometimes be translated as because, but they feel different.

-아서/어서

• is a general cause-and-result connector
• can be used very broadly

-느라

• specifically suggests that someone was occupied with an action
• often implies that this caused a negative consequence
• often sounds like I was tied up with X, so Y didn’t happen

Compare:

• 등록금을 내서 여행 계획을 못 세웠어
  = Because I paid tuition, I couldn’t make travel plans.
  This is possible, but more neutral.

• 등록금을 내느라 여행 계획을 못 세웠어
  = I was busy paying tuition / paying tuition took so much out of me, so I couldn’t make travel plans.
  This sounds more natural if you want to emphasize being tied up by that action.

The -는 adds contrast or topical emphasis.

• 이번 달에 = this month
• 이번 달에는 = as for this month, at least this month, or this month in particular

So 이번 달에는 여행 계획을 못 세웠어 suggests something like:

• This month, at least, I couldn’t make travel plans
• maybe other months are different
• or the speaker is highlighting this month as the important timeframe

This kind of -는 often adds a subtle contrast, even if it is not explicitly stated.

세우다 literally means to stand up, to erect, or to set up, but in many expressions it means to establish or to formulate.

So:

• 계획을 세우다 = to make a plan
• 여행 계획을 세우다 = to make travel plans / to plan a trip

This is a very common Korean collocation.
Even though 세우다 may not literally seem like make, the whole phrase naturally means to make/formulate a plan.

This is an important difference.

• 안 세웠어 = I didn’t make plans
  • sounds more like a choice or simple fact
• 못 세웠어 = I couldn’t make plans
  • suggests inability or that circumstances prevented it

In this sentence, the reason is that paying tuition got in the way. So 못 세웠어 is the better choice because the speaker means:

• I wasn’t able to make travel plans
• not just I chose not to

In Korean subordinate connectors like -느라, tense is often not marked directly on that part.

So instead of something like 냈느라, Korean usually keeps it as:

• 내느라

and the time reference is understood from the whole sentence, especially the main clause:

• 못 세웠어 = past tense

That makes the whole sentence understood as referring to a past situation:

• Because I was paying tuition, I couldn’t make travel plans this month

So even though 내느라 does not visibly show past tense, the sentence as a whole does.

Yes. The ending -어 in 세웠어 is casual/informal speech.

So this sentence sounds like something you would say to:

• a friend
• a sibling
• someone younger
• someone you are close to

A polite version would be:

• 등록금을 내느라 이번 달에는 여행 계획을 못 세웠어요.

The meaning is the same, but -어요 is polite.

Yes, the subject is omitted, which is very common in Korean.

From context, the implied subject is most naturally I:

• (나는) 등록금을 내느라 이번 달에는 여행 계획을 못 세웠어.

Korean often leaves out subjects when they are obvious from context.
Here, English normally needs I, but Korean does not.

Also, because of -느라, the same subject is understood for both actions:

• the person who paid the tuition
• is also the person who couldn’t make the travel plans

It can suggest both, depending on context.

Strictly speaking, -느라 focuses on being occupied by an action, so the most direct meaning is:

• because I had to deal with paying tuition
• because paying tuition took up my resources

But with 등록금, listeners often naturally also understand a money-related burden. So the sentence may imply:

• paying tuition took my time/attention
• and/or paying tuition made things financially tight

That is why the sentence feels very natural before something like:

• I couldn’t make travel plans
• because travel also requires money and planning

It depends on context, but the Korean form here is most naturally past, not present perfect.

Because of 못 세웠어, the basic reading is:

• I couldn’t make travel plans this month
• or I wasn’t able to make travel plans this month

In English, I haven’t made travel plans this month is possible in some contexts, but it sounds a bit more like a present status report. The Korean sentence feels more like the speaker is talking about what happened during the month and why it didn’t happen.

So the most natural translation is usually:

• I couldn’t make travel plans this month because I was busy paying tuition.