saitei ryoukin wo kakuninsita.

It is read:

さいてい りょうきん を かくにんした。

In normal writing, it would usually appear without spaces:

最低料金を確認した。

Yes, in this sentence 最低料金 functions as one noun phrase meaning minimum fee / lowest charge.

The spaces are likely just there to help learners see the parts:

• 最低 = minimum / lowest
• 料金 = fee / charge / fare

In ordinary Japanese writing, spaces are usually not used, so you would normally see:

最低料金を確認した。

Here, 最低 means minimum or lowest.

That is different from the conversational use of 最低 meaning awful or the worst.

For example:

• 最低料金 = minimum fee
• あいつは最低だ。 = He’s the worst.

So the meaning depends on context. In this sentence, because it comes before 料金, it clearly means minimum / lowest.

を marks the direct object of the verb.

The verb is 確認した (checked / confirmed), and the thing being checked is 最低料金. So:

• 最低料金 = the minimum fee
• を = marks it as the thing checked
• 確認した = checked / confirmed

So the structure is basically:

[minimum fee] + [object marker] + [checked]

確認した is the past plain form of 確認する.

• 確認 = confirmation / checking
• する = to do

Together, 確認する means to confirm or to check.

Then:

• 確認する = check / confirm
• 確認した = checked / confirmed

This is a very common pattern in Japanese: a noun + する to make a verb.

Other examples:

• 勉強する = to study
• 予約する = to reserve
• 確認する = to confirm

Japanese normally puts the verb at the end of the sentence.

So while English says:

I checked the minimum fee.

Japanese typically follows a pattern more like:

I / minimum fee / checked

That is why 確認した comes last.

This is one of the most basic word-order differences between English and Japanese.

Japanese often leaves out the subject when it is understood from context.

So this sentence could mean:

• I checked the minimum fee.
• We checked the minimum fee.
• Someone checked the minimum fee.

In many real situations, the listener already knows who did it, so Japanese does not need to say it explicitly.

If you wanted to include the topic, you could say:

• 私は最低料金を確認した。 = I checked the minimum fee.

But very often 私は is omitted.

確認した is the plain past form, so it sounds neutral or casual, depending on context.

A more polite version would be:

最低料金を確認しました。

So:

• 確認した = checked / confirmed (plain)
• 確認しました = checked / confirmed (polite)

The plain form is very common in casual speech, narration, notes, and informal writing.

These words are similar, but not exactly the same.

• 料金: a fee, charge, fare, or rate for a service or usage
  
  • train fare, admission fee, usage charge
• 値段: price in a broad, everyday sense
• 価格: price/cost, often a bit more formal or business-like

So 最低料金 sounds natural for things like:

• hotel fees
• phone charges
• admission fees
• transportation fares
• service rates

If you were talking about the lowest sticker price of a product, 最低価格 might be more natural in some contexts.

Yes. 確認する can mean both to check and to confirm, depending on context.

So this sentence could be understood as:

• I checked the minimum fee.
• I confirmed the minimum fee.

If the speaker looked it up for the first time, checked may sound more natural. If the speaker was making sure it was correct, confirmed may sound better.

Both are reasonable translations.

Sometimes, yes, but the nuance is a little different.

• 最低料金 = minimum fee / lowest fee
• 最安料金 = cheapest rate / lowest-priced rate

最安 focuses more directly on being the cheapest. 最低 often sounds like the minimum amount or lowest level.

In many practical contexts, both may appear, especially in travel or pricing situations, but they are not always perfectly interchangeable. 最低料金 is a very standard and safe expression.