Pelan prabayar ini murah.

The sentence has a very common Malay pattern:

[noun phrase] + [adjective]

• pelan prabayar ini = the subject, meaning this prepaid plan
• murah = the predicate adjective, meaning cheap

So the sentence structure is basically:

This prepaid plan + cheap

Malay often uses this structure where English would use is.

Because Malay usually does not need a present-tense verb like is / am / are in simple sentences with adjectives.

So:

• Pelan prabayar ini murah = This prepaid plan is cheap
• literally closer to This prepaid plan cheap

This is completely normal Malay.

You will see the same pattern in many sentences:

• Rumah itu besar = That house is big
• Buku ini baru = This book is new

In Malay, demonstratives usually come after the noun phrase.

So:

• buku ini = this book
• rumah itu = that house
• pelan prabayar ini = this prepaid plan

This is different from English, where this comes before the noun.

A useful rule:

• ini = this
• itu = that

and both usually go at the end of the noun phrase.

In this sentence, murah is the predicate, not just part of the noun phrase.

So:

• Pelan prabayar ini murah = This prepaid plan is cheap

Here, pelan prabayar ini is the thing being talked about, and murah says something about it.

Compare that with a noun phrase where murah directly modifies the noun:

• pelan prabayar murah ini = this cheap prepaid plan

So the position changes the meaning slightly:

• pelan prabayar ini murah = this prepaid plan is cheap
• pelan prabayar murah ini = this cheap prepaid plan

Malay does not have articles like English a, an, or the.

Whether something is definite or indefinite usually comes from context, or from words like ini and itu.

So:

• pelan prabayar can mean a prepaid plan or prepaid plan, depending on context
• pelan prabayar ini is clearly definite: this prepaid plan

In this sentence, ini already makes it specific.

Prabayar means prepaid.

It is made from:

• pra- = pre-
• bayar = pay

So the idea is paid in advance.

It is normally written as one word in Malay: prabayar.

This is a very common term in mobile/telecom contexts, so pelan prabayar is a natural phrase for prepaid plan.

You use tidak before the adjective:

• Pelan prabayar ini tidak murah = This prepaid plan is not cheap

Use tidak with adjectives and verbs.

For this sentence, bukan murah would not be the normal choice. Tidak murah is the natural form.

In everyday Malay, you can often make it a question just by using question intonation:

• Pelan prabayar ini murah? = Is this prepaid plan cheap?

In more formal Malay, you can use adakah:

• Adakah pelan prabayar ini murah?

Both are understandable, but the version without adakah is very common in speech.

You can add degree words before or after the adjective.

Common options:

• Pelan prabayar ini sangat murah = This prepaid plan is very cheap
• Pelan prabayar ini murah sekali = This prepaid plan is very cheap
• Pelan prabayar ini agak murah = This prepaid plan is quite/rather cheap

A quick guide:

• sangat = very
• sekali = very, extremely, often used after the adjective
• agak = rather, quite

A simple learner-friendly pronunciation is:

• pelan ≈ peh-lahn
• prabayar ≈ prah-bah-yar
• ini ≈ ee-nee
• murah ≈ moo-rah

A few tips:

• Malay vowels are usually more consistent than English vowels.
• r is usually clearer/trill-like compared with English r.
• The h in murah is pronounced, though often lightly.
• Malay stress is usually not as strong as in English, so try to keep the syllables fairly even.