Comma before "but"

Do I need a comma before "but"?

I like your car but it seems to me too expensive for you.

Or

I like your car, but it seems to me too expensive for you.

My native languages are Ukrainian and Russian. In these languages this comma is required.

Answer

Either is ok. Commas indicate a pause. If you want to emphasize the contrast between the two clauses more, add the comma.

By the way you don't need the "to me" in that sentence; it's implied by the fact that the sentence is written in the first person ("I" is the subject).

I like your car, but it seems too expensive for you.

Advice from the BBC:

A comma (,) generally indicates pauses in speech. But, when it joins two clauses, it indicates a contrast between two ideas. In speech it is normal to draw attention to this contrast by a slight pause. A comma is the usual way of indicating this, although it is not obligatory:

Sheila can eat anything and large quantities of it, but she never puts on weight.

I'm going to make some New Year resolutions, but I don't suppose I'll keep them