Kami tawar-menawar lalu membeli barang bekas itu.

In Indonesian, kami means we, but not you (exclusive), while kita means we including you (inclusive).

So in Kami tawar-menawar lalu membeli barang bekas itu, the speaker is talking about a group that does not include the listener.

• kami = we / us, excluding the person being spoken to
• kita = we / us, including the person being spoken to

This distinction is very important in Indonesian and often has no direct equivalent in natural everyday English.

Tawar-menawar means to bargain, to haggle, or to negotiate a price.

It comes from the idea of back-and-forth bargaining in a market or sale situation. In this sentence, it describes the action that happened before the purchase.

So:

• Kami tawar-menawar = We bargained / haggled

Depending on context, it can also refer to bargaining as a process or activity.

This is a form of reduplication, which is very common in Indonesian.

In this case, tawar-menawar is not simple plural marking. Instead, the repeated form gives the sense of a reciprocal or interactive process: bargaining involves two sides going back and forth.

So this is different from English repetition. It is a normal lexical form in Indonesian.

A rough way to think about it is:

• tawar = offer/bid, bargain
• tawar-menawar = bargaining back and forth

Not every repeated form works the same way in Indonesian, so it is best to learn tawar-menawar as a set expression.

It can function as either, depending on context.

In this sentence, it works like a verb phrase:

• Kami tawar-menawar lalu membeli...
• We bargained and then bought...

But in another sentence, it can act more like a noun:

• Tawar-menawar itu berlangsung lama.
• The bargaining lasted a long time.

This flexibility is common in Indonesian, where many words can function as different parts of speech depending on position and context.

Lalu means then, after that, or next. It shows sequence.

So here:

• Kami tawar-menawar lalu membeli...
• We bargained, then bought...

If you used dan, it would simply mean and, without emphasizing the order as clearly:

• Kami tawar-menawar dan membeli barang bekas itu.
• We bargained and bought that used item.

That version is possible, but lalu makes the timeline clearer: first bargaining, then buying.

Membeli is the meN- form of beli (to buy).

• beli = buy / to buy
• membeli = to buy, in a more standard full verb form

The prefix meN- is very common for active verbs in Indonesian. It often appears in more neutral or formal written language.

So:

• Kami membeli barang bekas itu = We bought that used item / those second-hand goods

In casual speech, Indonesians may sometimes say just beli, but membeli is grammatically complete and very normal.

The meN- prefix changes shape depending on the first sound of the root word. This is a normal sound adjustment in Indonesian.

With beli, the prefix becomes mem-:

• meN- + beli → membeli

Some other examples:

• meN- + baca → membaca
• meN- + pakai → memakai
• meN- + tulis → menulis

So membeli is just the expected form after adding the active verb prefix to beli.

Barang means item, thing, or goods.
Bekas means used, second-hand, or not new.

So barang bekas means:

• used goods
• second-hand item(s)

Depending on context, English might translate it as singular or plural:

• that used item
• those second-hand goods

Indonesian nouns do not have to show singular/plural the way English does, so context decides.

Not always. Bekas has several related meanings depending on context.

Common meanings include:

• used / second-hand
  
  • barang bekas = used goods
• mark / trace / scar / remains of
  • bekas luka = scar
  • bekas rumah itu = the remains/site of that house
• former / ex- in some contexts
  • bekas pacar = ex-boyfriend/ex-girlfriend

So in barang bekas, it clearly means used or second-hand.

In Indonesian, demonstratives like ini (this) and itu (that) usually come after the noun.

So:

• barang itu = that item / those goods
• barang bekas itu = that used item / those second-hand goods

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

The normal Indonesian pattern is:

• noun + adjective + itu/ini

Examples:

• rumah besar itu = that big house
• mobil baru ini = this new car

So barang bekas itu is completely normal Indonesian word order.

It can be either, depending on context.

Indonesian nouns usually do not change form for singular vs. plural. So barang can mean:

• an item
• items
• goods

Because of that, barang bekas itu could mean:

• that used item
• those used items
• those second-hand goods

If the original context does not make the number clear, English translators choose the most natural option.

Indonesian does not usually mark tense on the verb the way English does.

So:

• membeli can mean buy, bought, will buy, depending on context

Time is usually understood from:

• context
• time words such as kemarin (yesterday), tadi (earlier), besok (tomorrow)
• the flow of the story

In your sentence, the sequence tawar-menawar lalu membeli strongly suggests past actions in a narrative context, so English naturally translates it as bargained and then bought.

Yes, in some contexts it could be omitted if it is already clear who is being talked about.

For example, in conversation or in a story:

• Tawar-menawar lalu membeli barang bekas itu.

This could work if the subject has already been established.

However, including kami makes the sentence clearer and more complete, especially for standalone use.

Indonesian often allows subjects to be dropped when context is obvious, but it is not required.

Yes, it is understandable and natural.

It means that we bargained first, then bought that used item / those second-hand goods.

A few close alternatives could also be natural, depending on style:

• Kami menawar lalu membeli barang bekas itu.
• Kami tawar-menawar, lalu membeli barang bekas itu.
• Setelah tawar-menawar, kami membeli barang bekas itu.

The original sentence is fine, especially if the speaker wants to highlight the bargaining process before the purchase.