Oszczędzam siedemdziesiąt złotych.

Because Polish often leaves out subject pronouns when the verb already shows who is doing the action.
The ending -am in oszczędzam tells you it means I.

So:

• Oszczędzam siedemdziesiąt złotych. = I save / I am saving seventy złoty.
• Ja oszczędzam siedemdziesiąt złotych. is also possible, but ja adds emphasis, like I am saving it.

Oszczędzam is the 1st person singular present tense form of oszczędzać.

That means it can express:

• I save
• I am saving
• sometimes I am trying to save / I save regularly

Polish present tense often covers both the simple present and the present continuous from English.

It is imperfective.

That matters because imperfective verbs are used for:

• ongoing actions
• repeated habits
• general processes

So Oszczędzam siedemdziesiąt złotych suggests a process or habit: I am saving that amount, or I save that amount.

A common perfective partner is zaoszczędzić. For example:

• Zaoszczędzę siedemdziesiąt złotych. = I will save / manage to save seventy złoty.

So the imperfective version focuses more on the activity, while the perfective version focuses more on the result.

No. Oszczędzać can also mean things like:

• to economize
• to conserve
• to spare

For example, depending on context, it can be used with time, energy, water, and so on.

But in Oszczędzam siedemdziesiąt złotych, because the object is an amount of money, the meaning is clearly about saving money.

Because after numbers like 5 and higher, Polish normally uses the genitive plural form of the counted noun.

So:

• 1 złoty
• 2 złote
• 3 złote
• 4 złote
• 5 złotych
• 70 złotych

That is why siedemdziesiąt złotych is correct.

A very useful pattern to remember is:

• 1 → złoty
• 2–4 → złote
• 5 and up → złotych

The whole phrase is the object of the verb, so it functions as an accusative object.

However, Polish number phrases work differently from ordinary nouns. With numbers like 70, the numeral phrase takes this typical pattern:

• the numeral itself appears in a form used for nominative/accusative
• the counted noun appears in the genitive plural

So in siedemdziesiąt złotych, złotych is genitive plural because it follows a higher number.

This mixed behavior is normal in Polish numeral constructions.

A rough English-friendly guide is:

osh-CHEN-dzam shye-dem-JEEN-shont ZWO-tikh

A few useful sound notes:

• szcz sounds roughly like shch
• ę in oszczędzam sounds close to en here
• ł sounds like English w
• zł at the start of złotych sounds roughly like zw

Stress in Polish usually falls on the next-to-last syllable, so here the stress is on:

• oszCZĘdzam
• siedemDZIEsiąt
• ZŁOtych

Yes. Polish word order is more flexible than English.

The most neutral version is:

Oszczędzam siedemdziesiąt złotych.

But you could also say:

• Siedemdziesiąt złotych oszczędzam.
  This puts more focus on the amount.

• Ja oszczędzam siedemdziesiąt złotych.
  This emphasizes that I am the one saving it.

So the basic meaning stays the same, but the emphasis can shift.

It can mean either one, depending on context.

Polish present tense often covers both ideas that English separates:

• I save
• I am saving

So this sentence could describe:

• a habit: I save seventy złoty
• a current action/process: I am saving seventy złoty

Context tells you which meaning is intended.

Not exactly. In English, people often use zloty or zlotys without changing the form much. In Polish, the word changes form depending on the number.

The main forms are:

• złoty = 1
• złote = 2, 3, 4
• złotych = 5 and more

So siedemdziesiąt złotych is the natural Polish form for 70 złoty.

In writing, Polish also very often uses the abbreviation:

• 70 zł

So you may see:

Oszczędzam 70 zł.