Jag hittade ett mynt i jackan, men jag behöver mer växel till bussen.

Because Swedish nouns belong to two grammatical genders:

• en-words (common gender)
• ett-words (neuter)

In this sentence:

• mynt is an ett-word → ett mynt
• jacka is an en-word → en jacka
• buss is an en-word → en buss

So the forms are:

• ett mynt = a coin
• en jacka = a jacket
• en buss = a bus

You have to learn the gender along with the noun, since it affects articles and other forms.

In Swedish, the definite article is usually added to the end of the noun instead of being a separate word like the in English.

So:

• en jacka = a jacket
• jackan = the jacket

The same pattern appears with:

• en buss = a bus
• bussen = the bus

For en-words, the definite ending is often -n or -en, depending on the noun.

Hittade is the past tense of hitta, meaning to find.

• hitta = find
• hittar = find / am finding / do find (present)
• hittade = found (past)

So Jag hittade ett mynt means I found a coin.

This is a very common pattern for regular verbs in Swedish: the past tense often ends in -de or -te.

Because växel here means change as money, and in this sense it is treated as an uncountable noun.

So Swedish uses:

• mer = more, with uncountable things
• fler = more, with countable plural nouns

Compare:

• mer växel = more change
• fler mynt = more coins

So mer växel is correct because the speaker needs a greater amount of change, not a greater number of separately counted items.

Because växel here is being used as a mass/uncountable noun, like money or change in English.

So Swedish normally says:

• Jag behöver växel = I need change
• Jag behöver mer växel = I need more change

You would not usually say en växel in this meaning.

Also, be aware that växel can have other meanings in other contexts, such as gear or switchboard, but here it clearly means change.

Here till means something like for.

So mer växel till bussen means more change for the bus, in other words, change to pay the bus fare.

Till has several common meanings in Swedish, including:

• to
• for
• toward

In this sentence, for is the best way to understand it.

Because the sentence refers to a specific, understood bus situation: the bus the speaker is going to take or pay for.

Swedish often uses the definite form in situations where English may or may not use the. Transport expressions especially often sound natural with the definite form:

• ta bussen = take the bus
• springa till bussen = run to the bus
• växel till bussen = change for the bus

So bussen sounds natural because it refers to the relevant bus ride in context.

Yes. Men means but, and it is a coordinating conjunction, so the clause after it keeps normal main-clause word order:

• jag behöver = I need

So:

• ..., men jag behöver mer växel ...

This is different from some other structures in Swedish where word order changes. For example, if you begin with an adverb, the verb often comes before the subject:

• Nu behöver jag mer växel = Now I need more change

But after men, the order is simply subject + verb.

Both can be possible in Swedish, but they are used a little differently.

• Jag hittade ett mynt ... = I found a coin ...
• Jag har hittat ett mynt ... = I have found a coin ...

Hittade is a simple past form and works well for telling what happened.

Har hittat is the present perfect and puts more emphasis on the result being relevant now.

In this sentence, the speaker tells a past event and then connects it to the present situation:

• I found a coin, but I need more change now.

That makes hittade sound very natural.

Yes, literally it means in the jacket, but in everyday use it often means in the pocket of the jacket or somewhere in it.

Swedish commonly uses i for things located inside clothing, bags, pockets, and similar spaces:

• i fickan = in the pocket
• i väskan = in the bag
• i jackan = in the jacket

So a native speaker would usually understand this naturally, even if the exact place inside the jacket is not specified.