En god værtsgave behøver ikke at være dyr; nogle gange tager jeg bare en buket eller chokolade med.

Because Danish normally writes compound nouns as a single word.

• vært = host
• gave = gift

So værtsgave literally means host gift, or more naturally in English, a gift for the host / a hostess gift.

The -s- in the middle is a linking sound that often appears in Danish compounds.

Because gave is a common-gender noun in Danish, so it takes en.

That gives you:

• en gave
• en god gave
• en god værtsgave

If the noun were neuter gender, you would use et, and the adjective would often change too:

• et dyrt hus = an expensive house

So here:

• en because værtsgave is common gender
• god because it agrees with a common-gender singular noun

It means does not need to be.

Breakdown:

• behøver = needs
• ikke = not
• at være = to be

So:

• En god værtsgave behøver ikke at være dyr
  = A good host gift does not need to be expensive

This is a very common Danish pattern:

• Du behøver ikke at komme = You do not need to come
• Det behøver ikke at være svært = It does not need to be difficult

Not always. With behøve, Danish often allows both:

• behøver ikke at være
• behøver ikke være

Both are natural, and both mean the same thing here.

Including at is very common and sounds fully standard. Learners will often hear both versions.

Because in Danish main clauses, ikke usually comes after the finite verb and before the infinitive or the rest of the verbal phrase.

Here the finite verb is behøver, so the order is:

• behøver ikke at være

Compare:

• Jeg kommer ikke = I am not coming
• Han vil ikke spise = He does not want to eat
• Det behøver ikke at være dyrt = It does not need to be expensive

So the negation ikke is in its normal position.

Nogle gange means sometimes.

Literally, it is something like some times, but in natural English you usually translate it as sometimes.

Examples:

• Nogle gange cykler jeg på arbejde = Sometimes I bike to work
• Nogle gange er hun sen = Sometimes she is late

It is written as two words in Danish.

Because Danish is a verb-second language in main clauses.

When you move something like nogle gange to the front of the sentence, the verb must still stay in the second position. So you get inversion:

• Nogle gange tager jeg ...

instead of:

• Jeg tager nogle gange ...

Both are possible, but they have slightly different focus:

• Jeg tager nogle gange ... = neutral statement
• Nogle gange tager jeg ... = puts a little more emphasis on sometimes

This is a very important Danish word-order rule.

Here bare means just or simply.

So:

• jeg tager bare en buket eller chokolade med
  = I just bring a bouquet or chocolate

It suggests that the action is simple, easy, or not a big deal.

Compare:

• Jeg spørger bare = I’m just asking
• Tag bare en stol = Just take a chair

Because tage med is a verb expression meaning to bring / take along, and med is the particle that belongs with tage.

In Danish, that particle often appears later in the clause:

• Jeg tager en buket med
• Hun tog sin ven med

So even though tage med belongs together in meaning, the object can come in between.

This is very common in Danish:

• skrive ... ned = write down
• tage ... med = bring along
• finde ... frem = find / get out

Because chokolade here is being used as a mass noun, like chocolate in English.

So it means chocolate in a general sense:

• en buket = a bouquet
• chokolade = chocolate

If you wanted to refer to one individual piece, you would normally say something more specific, for example:

• et stykke chokolade = a piece of chocolate
• en æske chokolade = a box of chocolates

So the sentence is natural as it is.

Yes. In this sentence, dyr means expensive.

Danish dyr can mean two different things depending on how it is used:

• dyr as an adjective = expensive
• et dyr as a noun = an animal

Here it is clearly an adjective describing værtsgave, so it means expensive:

• en dyr gave = an expensive gift

The semicolon links two complete clauses that are closely related:

• En god værtsgave behøver ikke at være dyr
• nogle gange tager jeg bare en buket eller chokolade med

It is stronger than a comma, but not as final as a full stop.

You could also write this as two sentences:

• En god værtsgave behøver ikke at være dyr. Nogle gange tager jeg bare en buket eller chokolade med.

The semicolon simply shows that the two ideas belong closely together.