Learn Turkish: Bu bilgisayar bin dolar. - This computer is a thousand dollars.

In English we say "a thousand" or "one thousand", but in Turkish you don't use bir (one) before 100 or 1,000. You simply say yüz (a hundred) or bin (a thousand).

Why is dolar singular? Shouldn't it be dolarlar since there are a thousand of them?

In Turkish, nouns always stay in their singular form when they come directly after a number. Because the number bin already tells us there is more than one, you just say bin dolar, never bin dolarlar.

The current lesson is about var (there is). Why isn't it used here?

The word var is used to say that something exists somewhere (like "There is a computer on the table"). This sentence isn't saying a thousand dollars exists; it's just describing the computer's price. For basic "is/are" descriptive statements like this, Turkish doesn't use var.

Where is the word for "is" in this sentence?

There isn't one! In the present tense, Turkish often drops the "is" or "are" completely. By simply putting the subject (Bu bilgisayar) next to its price (bin dolar), the "is" is automatically understood by Turkish speakers.