Poupo todos os meses, mesmo que haja um défice.

Poupo is the 1st person singular present indicative of poupar.

• poupar = to save
• poupo = I save

So the speaker is talking about their regular habit or usual action.

Portuguese often drops the subject pronoun when the verb ending already makes the subject clear.

• Poupo already clearly means I save
• Eu poupo is also correct, but it usually adds emphasis, contrast, or clarity

So Poupo todos os meses is completely natural.

Yes. The present tense here describes a habitual or repeated action.

todos os meses means every month, so the sentence is not about one single moment. It means this is something the speaker does regularly.

Todos os meses is a very common way to say every month.

Literally, it is all the months, but in natural English we translate it as every month.

A similar alternative is cada mês, but todos os meses is extremely common and natural in everyday Portuguese.

Mesmo que introduces a concession: something is true despite another situation.

In many cases, it is closest to even if in English.

So the idea is:

• I save every month
• this remains true even if there is a deficit

It signals that the second idea does not stop the first one from being true.

Because mesmo que normally requires the subjunctive.

• há = present indicative
• haja = present subjunctive

After mesmo que, Portuguese uses the subjunctive because the clause expresses something possible, hypothetical, or irrelevant to the main action rather than a simple stated fact.

So:

• mesmo que haja um défice = correct
• mesmo que há um défice = not correct

Haja comes from haver.

Here, haver is being used in its impersonal existential sense, meaning there is / there are.

So:

• há um problema = there is a problem
• mesmo que haja um problema = even if there is a problem

In your sentence:

• mesmo que haja um défice = even if there is a deficit

In standard Portuguese, haver is the normal verb for there is / there are in more formal or neutral language.

So:

• há um défice = there is a deficit

In some varieties, especially in spoken Brazilian Portuguese, people often use ter in this existential sense, but in European Portuguese and in standard written Portuguese, haver is the expected choice here.

Because the clause needs the subjunctive, há becomes haja.

Yes. In European Portuguese, défice is a masculine noun:

• o défice
• um défice

That is why the sentence uses um.

The article also sounds natural because the speaker is referring to a deficit / some deficit, not to the idea of deficit in a completely abstract way.

Yes, défice is the usual European Portuguese form.

In Brazilian Portuguese, you will very often see déficit instead.

So this sentence clearly looks like Portugal Portuguese.

They are similar, because both can introduce a concessive idea, but they are not always used in exactly the same way.

In this sentence, mesmo que is especially close to even if. It often suggests that the condition does not change the result.

• Poupo todos os meses, mesmo que haja um défice. = I save every month, even if there is a deficit.

Embora is often closer to although / even though.

Both are followed by the subjunctive, but mesmo que often feels more clearly conditional or hypothetical.

Yes. You could also say:

Mesmo que haja um défice, poupo todos os meses.

This keeps the same basic meaning. The difference is mainly one of focus and style:

• Poupo todos os meses, mesmo que haja um défice.
  starts with the main point: I save every month
• Mesmo que haja um défice, poupo todos os meses.
  starts with the concessive idea: even if there is a deficit

Both are natural.

The comma separates the main clause from the subordinate concessive clause.

• main clause: Poupo todos os meses
• subordinate clause: mesmo que haja um défice

This punctuation is very natural in writing because it helps show the pause and structure of the sentence.