Billetten er billigere i appen end ved automaten.

Billetten is the definite singular form, meaning the ticket.

Danish often uses the definite form when talking about a specific item in a practical situation, even if English might sometimes use a ticket more naturally. Here, the idea is basically the ticket you are buying.

• en billet = a ticket
• billetten = the ticket

So Billetten er billigere ... means The ticket is cheaper ...

Billigere is the comparative form of billig, which means cheap.

So:

• billig = cheap
• billigere = cheaper
• billigst = cheapest

In this sentence, billigere is used because two buying options are being compared:

• i appen = in the app
• ved automaten = at the machine

So the pattern is:

X er billigere end Y = X is cheaper than Y

End means than in comparisons.

So:

• billigere end = cheaper than
• større end = bigger than
• hurtigere end = faster than

In the sentence:

i appen end ved automaten = in the app than at the machine

This is a very common Danish comparison structure.

In Danish, i appen is the normal way to say in the app.

The preposition i is used because the app is treated like a kind of digital space or environment you are inside of.

• i appen = in the app
• i programmet = in the program
• i systemet = in the system

Using på appen would usually sound unnatural here.

Ved automaten means at the machine or by the machine, and that is the natural Danish expression here.

It refers to buying the ticket at the ticket machine.

Compare:

• ved automaten = at the machine
• på automaten = on the machine, on top of it, or physically on its surface
• i automaten = in the machine, inside it

So if you are talking about the place or method of purchase, ved automaten is the correct choice.

Because Danish usually puts the at the end of the noun as a suffix.

So:

• en automat = a machine
• automaten = the machine

The same happens with:

• en billet = a ticket
• billetten = the ticket
• en app = an app
• appen = the app

This is one of the biggest differences from English.

The sentence as given is completely natural:

Billetten er billigere i appen end ved automaten.

But Danish word order can change if you want to emphasize something. For example:

I appen er billetten billigere end ved automaten.

This still means the same thing, but now i appen is emphasized more.

What stays the same is the comparison structure:

billigere ... end ...

And in a main clause, Danish normally keeps the finite verb in second position.

Yes, app is a borrowed word from English, but it behaves like a normal Danish noun.

So you get:

• en app = an app
• appen = the app
• apps = apps
• appene = the apps

Even borrowed words usually take normal Danish endings.

Yes, and that is a very natural alternative.

It means something like It is cheapest to buy the ticket in the app.

The difference is:

• Billetten er billigere i appen end ved automaten = direct comparison between two options
• Det er billigst at købe billetten i appen = says the app is the cheapest option overall

So both are correct, but they are structured differently.

It usually implies both.

In this sentence, ved automaten does not just mean physically standing near the machine. It naturally means when buying it from the machine or at the ticket machine.

So the sentence is really comparing two purchase methods:

• buying in the app
• buying at the machine

That is why the sentence sounds very natural in Danish.