susuryoga bissaseo chinguhante baro songgeumhaesseo.

Here, 비싸서 means because it was expensive.

It comes from:

• 비싸다 = to be expensive
• -아서/어서 = a connector meaning because, so, or sometimes just linking two actions

So 수수료가 비싸서 gives the reason for what happened next: the fee was expensive, so the speaker transferred the money directly to a friend.

In this sentence, -서 is best understood as a reason/cause marker.

Both can mean because, but they feel a little different.

• 비싸서 sounds more like a neutral explanation of the situation.
• 비싸니까 can sound a bit more assertive, judgment-based, or like the speaker is using that reason to justify a decision.

So:

• 수수료가 비싸서 친구한테 바로 송금했어
  = a natural, matter-of-fact explanation

• 수수료가 비싸니까 친구한테 바로 송금했어
  = also possible, but it can feel a bit more like since the fee was expensive, I went ahead and transferred it to my friend

In everyday narration, -서 is very common and natural here.

가 marks 수수료 as the thing that is expensive.

So 수수료가 비싸서 means roughly the fee was expensive.

If you used 수수료는, it would add more of a topic or contrast feeling, like:

• As for the fee, it was expensive
• The fee, though, was expensive

That version is possible in the right context, but 수수료가 비싸서 is the most neutral and straightforward wording.

In Korean, words like 비싸다 are often called descriptive verbs or adjectives, but grammatically they conjugate much like verbs.

So instead of using a separate word like is, Korean just changes the adjective itself:

• 비싸다 = to be expensive
• 비싸서 = because it is/was expensive
• 비쌌어 = it was expensive

This is very normal in Korean. English speakers often expect an adjective plus to be, but Korean usually does not work that way.

Korean usually does not mark articles like a or the, and it often does not force you to mark singular vs. plural either.

So 수수료가 비싸서 could be understood as:

• because the fee was expensive
• because fees were expensive
• because the transaction fee was high

The exact meaning depends on context.

In this sentence, English often translates it as the fee or the transfer fee, even though Korean does not explicitly say the.

Yes, 친구에게 would also be possible.

Both 한테 and 에게 can mean to when the receiver is a person.

• 친구한테 = to a friend
• 친구에게 = to a friend

The difference is mainly style:

• 한테 sounds more conversational and casual
• 에게 sounds a bit more neutral or written

Since the sentence ends with 했어, which is casual speech, 친구한테 matches the tone very well.

바로 can mean several related things, including:

• right away / immediately
• directly
• straight

In this sentence, it most likely means something like:

• directly to my friend
• right away to my friend

The exact nuance depends on context.

If the situation is about avoiding service fees or middle steps, 바로 may emphasize directly.
If the situation is about acting quickly, it may emphasize immediately.

Very often, it carries both ideas at once.

송금하다 is specifically about transferring money, especially in a financial or banking sense.

• 송금하다 = to remit / transfer money
• 보내다 = to send

So 송금했어 is more precise than 보냈어.

Compare:

• 친구한테 돈을 보냈어 = I sent money to my friend
• 친구한테 송금했어 = I transferred money to my friend

The second one sounds more specific to an actual money transfer.

It comes from:

• 송금 = remittance, money transfer
• 하다 = to do

Together:

• 송금하다 = to transfer money

Then it changes to past casual form:

• 송금했어 = transferred money / did a money transfer

This happens because many Korean verbs made from Sino-Korean nouns use 하다:

• 공부하다 = to study
• 운동하다 = to exercise
• 송금하다 = to transfer money

And in casual past tense:

• 공부했어
• 운동했어
• 송금했어

했어 is the casual informal style.

It is used with:

• close friends
• people younger than you
• family
• diaries or casual narration

The more polite version would be:

• 수수료가 비싸서 친구한테 바로 송금했어요.

So the original sentence sounds like relaxed everyday speech.

Yes. Korean often omits things that are clear from context.

In this sentence, the speaker does not explicitly say:

• I
• the money

But both are understood.

So the full idea is something like:

• I transferred the money directly to my friend because the fee was expensive.

This kind of omission is extremely common in Korean and usually sounds more natural than stating everything explicitly.