Learn Hardcore Swedish: Vi hyr inte bil i stan, eftersom bussen går ofta. - We do not rent a car in the city, since the bus runs often.

If you say Vi hyr inte en bil i stan, you put more focus on one particular car or one specific occasion:
We’re not renting a car (this time) in town.

What is the difference between Vi hyr inte bil i stan and Vi hyr ingen bil i stan?

Both are possible, but there is a nuance:

Vi hyr inte bil i stan.
– Negates the activity hyra bil.
– Sounds like a general habit or rule: We don’t (bother to) rent a car in town.
Vi hyr ingen bil i stan.
– ingen bil = no car / not any car.
– Focus on the quantity: not a single car.
– Slightly more emphatic: We’re not renting any car at all in town.

In everyday speech, both can work in this sentence. The version with inte bil ties in a bit more with the idea of hyra bil as a general activity.

What exactly does hyr mean, and how does it relate to hyra?

Hyra is the verb to rent / to hire. Its main forms:

Infinitive: att hyra – to rent
Present: hyr – rent / am renting / do rent
Past: hyrde – rented
Supine: hyrt – (have) rented

So Vi hyr inte bil i stan = We don’t rent a car in town.

Swedish present tense hyr can express:

Habit/general truth:
Vi hyr inte bil i stan. – We don’t (as a rule) rent a car in town.
Future based on a plan/decision:
Vi hyr inte bil i stan i sommar. – We’re not going to rent a car in town this summer.

Why is inte placed after hyr and not before, like Vi inte hyr bil?

In a normal main clause, Swedish follows the V2 rule: the finite verb is in second position, and sentence adverbs like inte, ofta, alltid usually come after that verb.

So:

Vi hyr inte bil …
Subject (Vi) – finite verb (hyr) – negation (inte) – object (bil)

The alternatives:

Vi inte hyr bil … – wrong word order
Vi hyr bil inte … – also unnatural in standard Swedish

You can move other parts of the sentence to the front, but the verb stays second and inte still follows it:

I stan hyr vi inte bil.
(In town, we don’t rent a car.)

Why do you say bussen går instead of something like bussen åker?

For public transport, Swedish normally uses gå for scheduled departures and routes:

Bussen går ofta. – The bus runs/comes often.
Tåget går 8.15. – The train leaves at 8:15.
Båten går bara på sommaren. – The boat only runs in summer.

So bussen går ofta = the bus runs frequently / there is a frequent bus service.

åka is used for people traveling, not for the vehicle’s schedule:

Jag åker buss. – I go by bus.
Vi åker tåg till Stockholm. – We go to Stockholm by train.

Saying bussen åker is odd in standard Swedish; you almost always want bussen går for this meaning.

Can ofta be put in a different place, like eftersom bussen ofta går?

Yes. Both versions occur:

eftersom bussen går ofta
eftersom bussen ofta går

General patterns:

In a main clause:
Bussen går ofta. – very normal.
In a subordinate clause (after eftersom, att, etc.), many grammar books give:
… eftersom bussen ofta går. – subject + adverb + verb.

In real spoken Swedish, eftersom bussen går ofta is also widely used and sounds natural.
If you want to be very textbook‑correct, eftersom bussen ofta går is the “safer” choice, but your sentence will definitely be understood and is quite normal in everyday language.

What is the difference between i stan, i staden, and i en stad?

All are based on stad (city/town):

i stan
- stan is the colloquial spoken form of staden.
- Means in town, usually the town/city we’re in / the city centre.
- Very common in everyday speech: Jag jobbar i stan.
i staden
- More formal or neutral than i stan.
- Refers to a specific city (already known in the context):
  Han bor i staden men jobbar på landet.
i en stad
- Indefinite: in a (some) city.
- Used when you don’t have a specific city in mind:
  Hon vill bo i en stad. – She wants to live in a city.

In your sentence, i stan sounds natural and colloquial: in town / in the city (where we are).

What is the difference between i stan and till stan?

i stan = in town – location, where you are:
Vi hyr inte bil i stan. – We don’t rent a car in town.
till stan = to town – movement towards town:
Vi åker buss till stan. – We go to town by bus.

Same pattern with many places:

i Sverige (in Sweden) vs till Sverige (to Sweden)
i skolan (in/at school) vs till skolan (to school)

When do you use eftersom compared to för att or därför att?

All three can mean because, but they behave a bit differently.

eftersom
- Very safe, neutral because.
- Often used for giving an explanation:
  Vi hyr inte bil i stan, eftersom bussen går ofta.
för att
- Can mean because, especially in speech:
  Vi hyr inte bil i stan, för att bussen går ofta.
- Also very commonly means in order to before an infinitive:
  Vi hyr bil för att resa runt. – We rent a car in order to travel around.
- This double meaning sometimes makes eftersom clearer.
därför att
- Also because, somewhat more formal/emphatic.
- Often used after Det är … or after a negation:
  Det är därför att bussen går ofta.
  Vi hyr inte bil därför att det är dyrt, utan därför att bussen går ofta.

In your sentence, eftersom is the most straightforward, unambiguous choice.

Why is there a comma before eftersom in Swedish, when English usually doesn’t put a comma before because?

Swedish comma rules differ from English:

It is common and acceptable to put a comma between a main clause and a following subordinate clause:
Vi hyr inte bil i stan, eftersom bussen går ofta.
Modern style guides often say the comma is optional here. So this is also correct:
Vi hyr inte bil i stan eftersom bussen går ofta.

In English, we normally avoid a comma before because unless we need it to avoid ambiguity. In Swedish, using the comma here is a matter of style rather than strict correctness; many teachers still prefer to include it.