menyupaneul orae boda boni gyeolguk jeil ssan gimbabeul jumunhaesseo.

-다 보니 is a very common Korean pattern that means:

• while doing something repeatedly
• after doing something for a while
• as I kept doing it, this result happened

So 메뉴판을 오래 보다 보니 means something like:

• As I kept looking at the menu for a long time...
• After staring at the menu for a while...
• Looking at the menu for so long, I ended up...

It often introduces a result that happened naturally, not something carefully planned from the start.

These forms are similar, but the nuance is different.

• 보다 보니: emphasizes an ongoing process that led to a result
  
  • As I kept looking... I ended up...
• 봐서: usually means because I saw / after seeing, more direct and less process-focused
• 보니까: often means when I looked, I found/realized

In this sentence, the speaker wants to show that spending time looking at the menu gradually led to the final decision, so 보다 보니 fits very well.

오래 is an adverb meaning for a long time.

So:

• 오래 보다 = to look at something for a long time

In this sentence, it modifies 보다, so the meaning is looked at the menu for a long time.

You could also see 오랫동안, which is similar:

• 오래 = for a long time
• 오랫동안 = for a long time / over a long period

Here 오래 sounds natural and conversational.

Because 메뉴판 is the object of 보다.

• 메뉴판을 보다 = to look at the menu/menu board

The particle 을/를 marks the direct object of the verb.

So in the first part:

• 메뉴판을 오래 보다 보니
  = as I kept looking at the menu for a long time

Because the sentence contains two different actions:

1. 메뉴판을 보다 = look at the menu
2. 김밥을 주문하다 = order kimbap

Each verb has its own object:

• 메뉴판을 goes with 보다
• 김밥을 goes with 주문했어

So the sentence is built like this:

• [메뉴판을 오래 보다 보니] [결국 제일 싼 김밥을 주문했어]

결국 means in the end, eventually, or after all.

It often suggests:

• there was some thinking, hesitation, or process before the final result
• the final result may not have been the original plan

So here:

• 결국 제일 싼 김밥을 주문했어
• In the end, I ordered the cheapest kimbap

It matches the feeling of someone looking at the menu for a while and then finally deciding.

Because 싸다 here means to be cheap, and it is an adjective/descriptive verb in Korean.

When Korean adjectives modify a noun, they usually use -ㄴ/은:

• 싸다 → 싼
• 예쁘다 → 예쁜
• 작다 → 작은

So:

• 싼 김밥 = cheap kimbap
• 제일 싼 김밥 = the cheapest kimbap

싸는 would be used with the verb 싸다 meaning to wrap/pack, not with 싸다 meaning cheap.

The base form is 싸다 (to be cheap).

To modify a noun, Korean descriptive verbs often take -ㄴ if the stem ends in a vowel:

• stem: 싸-
• modifier form: 싼

So:

• 싸다 → 싼
• 비싸다 → 비싼

That is why 제일 싼 김밥 means the cheapest kimbap.

Both usually mean the most.

So these are both natural:

• 제일 싼 김밥
• 가장 싼 김밥

In everyday speech, 제일 is often a little more conversational, while 가장 can sound a bit more neutral or formal. In this sentence, 제일 sounds very natural.

주문했어 is:

• past tense
• casual/informal speech

Breakdown:

• 주문하다 = to order
• 주문했어 = ordered

So the speaker is talking casually to someone they are close to.

Other versions:

• 주문했어요 = polite
• 주문했습니다 = formal
• 주문해 = casual present/future depending on context

Yes. 주문하다 is a standard verb meaning to order.

So:

• 김밥을 주문하다 = to order kimbap

In restaurants, Koreans also often use 시키다 for ordering food:

• 김밥을 시켰어 = I ordered kimbap

The difference is roughly:

• 주문하다 = a bit more direct and standard, often used in many contexts
• 시키다 = very common in food-ordering situations

In your sentence, 주문했어 sounds completely natural.

Often, yes.

-다 보니 frequently carries the nuance that something happened as a result of the process, almost like I ended up...

So this sentence can feel like:

• the speaker kept looking at the menu
• maybe they were comparing options
• and in the end, they wound up choosing the cheapest kimbap

That is why 결국 works so well here too. Together, 보다 보니 and 결국 make the sentence feel natural and a little reflective:

• I kept looking at the menu for so long that, in the end, I just ordered the cheapest kimbap.

Korean often puts background information first and the main result later.

This sentence can be divided like this:

• 메뉴판을 오래 보다 보니
  As I kept looking at the menu for a long time,
• 결국 제일 싼 김밥을 주문했어.
  in the end I ordered the cheapest kimbap.

So the flow is:

1. what was happening
2. what result came from it

That is a very common Korean sentence pattern.