Subskrypcja, abonament, rata i ubezpieczenie kosztują dużo.

Because the subject is plural: there are four things listed — subskrypcja, abonament, rata i ubezpieczenie.

In Polish, when several nouns are joined together, the verb normally agrees with the whole group, so you use the 3rd person plural form:

• kosztuje = costs (singular)
• kosztują = cost / are costing (plural)

So:

• Subskrypcja kosztuje dużo. = The subscription costs a lot.
• Subskrypcja, abonament, rata i ubezpieczenie kosztują dużo. = The subscription, the plan, the installment, and the insurance cost a lot.

Because they are the subject of the sentence, so they appear in the nominative case.

The sentence answers the question What costs a lot?
Answer: subskrypcja, abonament, rata i ubezpieczenie.

That is why you see the base forms:

• subskrypcja
• abonament
• rata
• ubezpieczenie

If these words had a different role in the sentence, they might change form.

They can both relate to subscription, but they are not always used in exactly the same way.

A rough guide:

• subskrypcja often sounds more like a subscription to a service or content, especially modern/digital contexts

  • subskrypcja platformy streamingowej
  • subskrypcja newslettera

• abonament often means a plan, recurring paid access, or a subscription arrangement

  • abonament telefoniczny = phone plan
  • abonament miesięczny = monthly subscription/pass
  • abonament na siłownię = gym membership/subscription

In some contexts they overlap, but they are not always interchangeable. A learner should treat them as related but not identical words.

Rata means an installment — one payment that is part of a larger total.

For example:

• buying something on credit and paying in monthly parts
• paying off a loan
• paying for insurance in several installments

So rata kosztuje dużo would mean the installment is expensive / the installment costs a lot.

It is singular here because the sentence is talking about the concept of an installment payment, not necessarily several installments.

Because kosztować dużo is the normal way to say to cost a lot.

• dużo = a lot
• drogo = expensively / at a high price

Natural Polish patterns are:

• To kosztuje dużo. = This costs a lot.
• To jest drogie. = This is expensive.

So in this sentence:

• kosztują dużo = cost a lot

You would not normally say kosztują drogo here.

Yes, often you can express a similar idea that way:

• Subskrypcja, abonament, rata i ubezpieczenie są drogie.

That means The subscription, the plan, the installment, and the insurance are expensive.

The difference is small but useful:

• kosztują dużo focuses on the amount of money paid
• są drogie describes them as expensive things

Both are natural, but kosztują dużo is a very direct way to talk about cost.

Because Polish does not have articles like English a/an and the.

So:

• subskrypcja can mean a subscription or the subscription
• abonament can mean a plan/subscription or the plan/subscription

The exact meaning depends on context.

That is very normal in Polish, and learners have to get used to understanding definiteness from the situation rather than from an article.

Because in Polish, just like in English, you normally do not put a comma before the simple conjunction i when it means and in a basic list.

So this is correct:

• Subskrypcja, abonament, rata i ubezpieczenie kosztują dużo.

The commas separate the earlier items in the list, but there is no comma before the final i.

Yes, each noun has a grammatical gender:

• subskrypcja — feminine
• abonament — masculine inanimate
• rata — feminine
• ubezpieczenie — neuter

In this particular sentence, gender does not visibly change the present-tense verb form, because the subject is plural and the verb is simply kosztują.

But gender can matter elsewhere, especially with adjectives or in the past tense. For example:

• subskrypcja była droga
• abonament był drogi
• ubezpieczenie było drogie

And if all these things were talked about in the past as a plural group, you would say:

• kosztowały dużo

Both dużo and wiele can relate to a lot / many, but dużo is the natural choice here.

With kosztować, Polish very commonly uses:

• kosztować dużo
• kosztować mało

Examples:

• To kosztuje dużo. = It costs a lot.
• To kosztuje mało. = It costs little / not much.

Wiele is possible in some contexts, but it is less natural here. For a learner, kosztować dużo is the safest and most idiomatic pattern.

Yes. Polish word order is relatively flexible, although some versions sound more neutral than others.

The original sentence is neutral and straightforward:

• Subskrypcja, abonament, rata i ubezpieczenie kosztują dużo.

You could also say:

• Dużo kosztują subskrypcja, abonament, rata i ubezpieczenie.

This puts more emphasis on dużo.

So the meaning stays basically the same, but the emphasis changes. For learners, the original order is the best default.

It could be either, depending on context.

Because Polish has no articles, the sentence can mean:

• A subscription, a plan, an installment, and insurance cost a lot
  or
• The subscription, the plan, the installment, and the insurance cost a lot

Without context, it often sounds a bit like a general statement about these kinds of expenses.

Yes, grammatically it is natural.

What may feel slightly unusual is not the grammar, but the choice of items together in one list, because they are somewhat mixed in meaning:

• subskrypcja — subscription
• abonament — plan/subscription/pass
• rata — installment
• ubezpieczenie — insurance

Still, as a grammar example, it is perfectly fine and useful because it shows:

• a list of nouns in the nominative
• plural verb agreement
• the pattern kosztować dużo

So a Polish speaker would understand it easily.