Vare sig avgiften är liten eller stor vill hon läsa kontraktet noggrant först.

No. They look similar, but they are used differently.

• vare sig ... eller ... = whether ... or ... / regardless of whether ... or ...
• antingen ... eller ... = either ... or ...

So here, vare sig fits because the sentence means the fee’s size does not change what she wants to do. Antingen ... eller ... would sound more like choosing between two alternatives.

This is because of normal Swedish V2 word order in main clauses. When something other than the subject comes first, the finite verb must come second.

Here, the opening part Vare sig avgiften är liten eller stor comes before the main clause, so the main clause becomes:

• vill = finite verb
• hon = subject

That is why Swedish says ... vill hon läsa ..., not ... hon vill läsa ....

Because vilja is a modal-like verb, and after verbs like vilja, kunna, måste, ska, and får, Swedish normally uses the infinitive without att.

So:

• hon vill läsa = she wants to read

not

• hon vill att läsa ✗

Avgiften is the definite form, meaning the fee. The sentence is talking about a specific fee, not just any fee in general.

• en avgift = a fee
• avgiften = the fee

So the speaker has a particular fee in mind, probably one mentioned earlier or understood from context.

Because liten and stor are predicate adjectives here, coming after är. In Swedish, adjectives used after vara do not take an article.

So you say:

• avgiften är liten
• avgiften är stor

not

• avgiften är en liten ✗
• avgiften är en stor ✗

This is similar to English: the fee is small, not the fee is a small.

Avgift usually means fee, charge, or payment of a specific kind. It often refers to something official, required, or fixed, such as a membership fee, service fee, application fee, or legal charge.

It is not always the same as the general word kostnad, which means cost/expense more broadly.

Because noggrant is being used adverbially: it describes how she wants to read the contract. The base adjective is noggrann = careful / thorough, and the -t form is often used as an adverb.

So:

• en noggrann person = a careful person
• läsa noggrant = read carefully / thoroughly

In other words, noggrant modifies the verb läsa.

Here först means first or before anything else. It shows that reading the contract carefully is something she wants to do before taking the next step.

So the idea is: she wants to read the contract carefully first, before agreeing, signing, paying, or deciding anything.

That position is very natural in Swedish. Short adverbs like först often come later in the clause, especially after the infinitive phrase.

So läsa kontraktet noggrant först sounds normal and idiomatic. If you move först, the sentence can still work, but the emphasis changes a little.

For example:

• Först vill hon läsa kontraktet noggrant.
  This gives more emphasis to first.

No. In Swedish, just like in English, you usually do not repeat the verb when it is shared.

So:

• avgiften är liten eller stor = correct

This is understood as avgiften är liten eller avgiften är stor, but Swedish normally leaves out the repeated material because it is already clear.

It sounds somewhat neutral-to-formal, especially because of vare sig and kontraktet. It would fit well in written Swedish, business Swedish, or careful speech.

In more everyday speech, some speakers might prefer something like:

• Oavsett om avgiften är liten eller stor vill hon läsa kontraktet noggrant först.

That said, the original sentence is completely natural and correct.

Usually, no comma is needed here in modern Swedish. Swedish uses fewer commas than English, and an initial subordinate clause is often followed directly by the main clause without a comma.

So this is fine:

• Vare sig avgiften är liten eller stor vill hon läsa kontraktet noggrant först.

A comma is not impossible in some styles, but leaving it out is standard.