Ayaw kong gumastos.

Here, ayaw means not want or don’t want. It is the common opposite of gusto (want / like).

So patterns like these are very common:

• Gusto kong kumain. — I want to eat.
• Ayaw kong kumain. — I don’t want to eat.

Depending on context, ayaw can also sound like refuse to, don’t feel like, or am unwilling to.

Kong is ko plus the linker -ng.

• ko = my / me / I in this kind of structure
• -ng links it to the next word, gumastos

So:

• Ayaw ko = I don’t want
• Ayaw kong gumastos = I don’t want to spend

That -ng is very common before another word that completes the idea. Without it, the sentence sounds incomplete or nonstandard.

Because with expressions like gusto and ayaw, Filipino normally uses ko rather than ako before another verb.

Compare:

• Ako ay pagod. — I am tired.
• Gusto kong umalis. — I want to leave.
• Ayaw kong gumastos. — I don’t want to spend.

So even though English uses I, Filipino often uses ko in this pattern. This is just a normal grammar pattern you need to get used to.

The root word is gastos, which is related to expense, cost, or spending.

Gumastos is the verb to spend. It is formed with the -um- verb pattern:

• gastos — expense / cost
• gumastos — to spend

This is an actor-focus verb, meaning the doer of the action is the focus.

This is a very common learner question.

For many -um- verbs, the form used after words like gusto, ayaw, kailangan, and similar expressions looks the same as the completed/past form.

So gumastos can mean:

• spent in one context
• to spend in another context

In Ayaw kong gumastos, it is understood as to spend, not necessarily spent. The surrounding words make that clear.

Usually, yes.

Gumastos most often refers to spending money or incurring an expense. If you want to make that explicit, you can say:

• Ayaw kong gumastos ng pera. — I don’t want to spend money.

If you are talking about spending time or effort, Filipino often uses other verbs depending on the situation.

Yes. The sentence is perfectly natural even without saying what is being spent.

Ayaw kong gumastos can stand on its own if the context is already clear. For example, maybe people are talking about going shopping, paying fees, or buying something expensive.

If you want to add more detail, you can:

• say what is spent: Ayaw kong gumastos ng pera.
• say what it is for: Ayaw kong gumastos para diyan.
• say what it is spent on: Ayaw kong gumastos sa damit.

Yes. Ayoko is a very common contraction of ayaw ko.

So these both work:

• Ayaw kong gumastos.
• Ayokong gumastos.

The second one is especially common in everyday speech and writing.

They are different.

• Ayaw kong gumastos = I don’t want to spend.
  This is about willingness or desire.

• Hindi ako gumagastos = I’m not spending / I don’t spend.
  This is about the action itself not happening, or a habit.

So the first means I don’t want to.
The second means I’m not doing it.

You could, and people would understand you, but Ayaw kong gumastos is more natural and more idiomatic for most situations.

Very roughly:

• Ayaw kong gumastos — I don’t want to spend.
• Hindi ko gustong gumastos — I do not like/want to spend.

The second one can sound a bit more formal, literary, or less direct. In everyday conversation, ayaw is usually the better choice here.

You can add more information after gumastos.

Common patterns:

• Ayaw kong gumastos ng pera. — I don’t want to spend money.
• Ayaw kong gumastos ng pera sa pagkain. — I don’t want to spend money on food.
• Ayaw kong gumastos para sa party. — I don’t want to spend for the party.
• Ayaw kong gumastos sa bagay na iyan. — I don’t want to spend on that thing.

A useful shortcut:

• ng often marks what is being spent
• sa often marks what it is spent on
• para sa often marks what it is for