У меня нет монет, поэтому я заплачу купюрой.

I don’t have any coins, so I will pay with a banknote.

Breakdown of У меня нет монет, поэтому я заплачу купюрой.

• я: I
• нет: no
• заплатить: to pay
• поэтому: so/therefore
• купюра: banknote
• монета: coin

Questions & Answers about У меня нет монет, поэтому я заплачу купюрой.

Why does it say у меня for “I have”? What does it literally mean?

Russian often expresses possession with the pattern у + GENITIVE + (есть/нет).
У меня literally means “at/by me,” i.e., “in my possession.”
So У меня нет монет is literally “At me there are no coins,” meaning “I don’t have any coins.”

Why is it нет монет and not нет монеты/монеты?

After нет (and generally after negation in this “there is/are not” structure), the noun is normally in the genitive case.
Here it’s genitive plural: монет = “(of) coins.”
Compare:

• Есть монеты = “There are coins / I have coins” (nominative plural)
• Нет монет = “There are no coins / I don’t have coins” (genitive plural)

What case is меня in у меня?

Меня is genitive of я (“I”). The preposition у requires the genitive:
у меня, у тебя, у него, у неё, у нас, etc.

Is нет a verb? Why isn’t there a form like не есть here?

Нет functions as a negative existential word (“there isn’t/aren’t,” “don’t have”) and is historically related to не + есть, but modern Russian normally uses нет as the standard form.
Using не есть in this meaning is not normal in modern speech.

What’s the role of поэтому, and why is there a comma before it?

Поэтому means “therefore / so / that’s why.” It links two clauses with a cause → result relationship.
A comma is used because you have two independent clauses:

• У меня нет монет,
• поэтому я заплачу купюрой.

Could I replace поэтому with something else like так что? What’s the difference?

Yes, common alternatives include:

• так что = “so (as a result)” (often more conversational)
• поэтому = “therefore / that’s why” (neutral, slightly more “logical-link” feeling) Examples:
• У меня нет монет, так что я заплачу купюрой.
• У меня нет монет, поэтому я заплачу купюрой.

Why is заплачу used—what tense/aspect is it?

Заплачу is the future form of the perfective verb заплатить (“to pay (successfully/once)”).
Perfective verbs don’t have a present tense meaning; their “present-looking” forms refer to the future:

• я заплачу = “I will pay (once)”

What would the imperfective version be, and when would I use it?

Imperfective: платить. Future imperfective uses буду + infinitive:

• я буду платить = “I will be paying / I will pay (in general, process-focused)” In this context (one specific payment right now), я заплачу (perfective) is the natural choice.

Why is купюрой in the instrumental case? What does it imply?

Купюрой is instrumental singular of купюра (“banknote/bill”). Instrumental is used for “by means of / with” after many verbs of paying:

• заплатить чем? → купюрой
  It implies the method/means: “I’ll pay with a bill.”

Could it also be купюрами or купюру?

• купюрами (instrumental plural) is possible if you mean multiple bills: заплачу купюрами.
• купюру (accusative) would be unnatural in this meaning; Russian typically uses instrumental for “pay with X.”
  You can say заплачу купюру only in a different sense (rare/odd), not the normal “pay with a bill” construction.

Is купюра the same as банкнота? Which is more common?

They’re very close:

• купюра = common, everyday “bill” (also used for denominations)
• банкнота = more formal/technical “banknote” In a shop, купюра sounds very natural.

Can I drop я and just say … поэтому заплачу купюрой?

Yes. Russian often omits subject pronouns because the verb ending shows the person:

• У меня нет монет, поэтому заплачу купюрой.
  This sounds natural in context. Keeping я can add a bit of emphasis/contrast (“so I will pay…”).