Мы ни разу не спорили друг с другом из‑за денег.

This is a normal Russian pattern called double negation or negative concord.

• не negates the verb: не спорили = did not argue
• ни разу strengthens that negation: not even once

So ни разу не спорили means didn’t argue even once or more naturally never argued.

In standard Russian, ни разу normally goes together with a negative verb. So Мы ни разу спорили would be incorrect.

They are close, but not identical.

• ни разу не = not once
• никогда не = never

In many situations they can both translate as never, but ни разу не emphasizes the number of times: zero times.

So this sentence is slightly more like:

• We never argued over money
• or more literally: Not once did we argue over money

Because Russian does not have a direct tense equivalent of the English present perfect.

English often uses have never argued for life experience up to now. Russian normally uses the past tense for that idea:

• Мы ни разу не спорили... = We have never argued...

So спорили is past tense in form, but in translation it can correspond to either:

• we didn’t argue
• we have never argued

The broader context tells you which English version sounds best.

This is about aspect.

• спорить is imperfective
• поспорить is the usual perfective partner

Here спорили is the most neutral way to say argued / were arguing / have argued as a general fact. The sentence is about whether that kind of situation ever happened, not about one specific completed argument.

Using поспорили is possible in some contexts, but it would sound a bit more like had an argument once or got into an argument.
With спорили, the meaning is broader and more natural here: we never argued with each other over money.

It means with each other.

This is a standard Russian reciprocal expression built from друг:

• друг друга = each other
• друг другу = to each other
• друг с другом = with each other

So:

• Мы спорили друг с другом = We argued with each other

Even though друг by itself usually means friend or one another in older/fixed uses, in this pattern the whole expression functions like each other.

After the preposition с meaning with, Russian normally uses the instrumental case.

That is why you get:

• с другом in the fixed reciprocal expression
• specifically другом, which is the instrumental form

So in друг с другом, the -ом ending shows the instrumental case required by с.

Из-за can indeed mean from behind, but here it means because of.

In this sentence:

• из-за денег = because of money
• in natural English: over money

So the idea is not physical location at all. It is the cause of the argument.

Also, из-за is written with a hyphen. That is just the standard spelling of this preposition.

Because из-за requires the genitive case, and деньги changes to денег in the genitive plural.

So:

• dictionary form: деньги
• after из-за: из-за денег

A useful extra point: деньги is a plural-only noun in modern Russian. Even when English uses singular money, Russian uses the plural form деньги.

That is why you learn it as:

• деньги = money
• нет денег = there is no money / no money
• из-за денег = because of money

Because that is simply how the noun works in Russian.

Деньги is treated grammatically as a plural noun, even though its meaning often matches English singular money.

So Russian says things like:

• деньги лежат на столе = the money is on the table
• у меня нет денег = I have no money

This is one of those vocabulary facts you just memorize with the word.

Yes. Russian word order is relatively flexible.

The neutral order here is:

• Мы ни разу не спорили друг с другом из-за денег.

But other orders are possible, for example to shift emphasis:

• Мы друг с другом ни разу не спорили из-за денег.
• Из-за денег мы ни разу не спорили друг с другом.

The basic meaning stays the same, but the focus changes slightly.
The original version sounds natural and neutral.

Yes, if the subject is already clear from context.

Russian often drops subject pronouns when they are not needed. So you could say:

• Ни разу не спорили друг с другом из-за денег.

That can still mean We never argued with each other over money, if the context makes it obvious who we are.

Including мы makes the subject explicit and can add a little emphasis or contrast.

Not exactly.

• спорить = to argue, dispute, disagree
• ссориться = to quarrel, fall out, have a personal conflict

Спорить can sound more like disagreement in words.
Ссориться often suggests a more emotional or serious quarrel.

So in this sentence, спорили из-за денег means argued over money.
If you said ссорились из-за денег, it could sound a bit stronger, more like quarreled because of money.