Kad budem došla kući, stavit ću kusur u torbicu i spremiti račun.

Budem došla is future II in Croatian.

It is formed with:

• the present tense of biti → budem
• plus the l-participle of the main verb → došla

So:

• budem došla = when I have come / when I get there / when I arrive

In this sentence, it is used because the arrival happens before the other future actions:

• first: I get home
• then: I’ll put the change in my handbag and put away the receipt

So the structure is roughly:

• Kad budem došla kući = When I get home
• stavit ću... = I will put...

Because the speaker is understood to be female.

In Croatian, the l-participle agrees with the subject in gender and number:

• došao = a man says I came / I will have come
• došla = a woman says I came / I will have come
• došli = plural masculine or mixed group
• došle = plural feminine

So this sentence is being said by a woman:

• Kad budem došla kući...

If a man were speaking, it would be:

• Kad budem došao kući...

Because Croatian normally does not use future I after time words like kad when talking about a future event.

So English allows:

• When I come home
• When I will come home → this is actually unnatural in English too

Croatian usually uses:

• kad dođem kući or
• kad budem došla kući

Not:

• kad ću doći kući

So after kad, Croatian typically prefers:

• a present form with future meaning, especially with a perfective verb
• or future II, especially when one future action is completed before another

Yes. Kad dođem kući is very common and natural.

So both are possible:

• Kad dođem kući, stavit ću kusur u torbicu i spremiti račun.
• Kad budem došla kući, stavit ću kusur u torbicu i spremiti račun.

The difference is subtle:

• kad dođem kući is very common in everyday speech
• kad budem došla kući can sound a little more explicit about the first action being completed before the next ones

For a learner, it is useful to recognize both.

Because ići kući and doći kući are fixed, very common expressions meaning to go home and to come home.

So:

• doći kući = to come home
• ići kući = to go home

This is idiomatic Croatian.

Compare:

• Idem kući. = I’m going home.
• Dolazim kući. = I’m coming home.

If you say u kuću, that usually means into the house/building physically, not just home in the general sense.

So:

• doći kući = come home
• doći u kuću = come into the house

Because in standard Croatian, when ću, ćeš, će, ćemo, ćete, će comes after an infinitive ending in -ti, the final -i is dropped.

So:

• staviti + ću → stavit ću
• spremiti + ću → spremit ću
• kupiti + ću → kupit ću

Not:

• staviti ću
• spremiti ću

You can also place the auxiliary before the infinitive:

• ću staviti
• ću spremiti

So these are correct:

• Stavit ću kusur u torbicu.
• Ću staviti kusur u torbicu.
  This is grammatically possible in structure, but in normal Croatian clitic placement, you would usually not start a sentence this way without something before it.

The important learner point is:

• stavit ću is the normal written form when the auxiliary follows the infinitive
• staviti ću is nonstandard

Because one ću can apply to both verbs.

So:

• stavit ću kusur u torbicu i spremiti račun

means:

• I will put the change in my handbag and put away the receipt

The second ću is understood from the first verb.

You could also say:

• stavit ću kusur u torbicu i spremit ću račun

That is also correct, but repeating ću is not necessary.

This is very common in Croatian when two infinitives share the same subject and tense.

Because after u, Croatian uses different cases depending on the meaning:

• accusative for movement into
• locative for location in

Here, the change is being moved into the handbag, so you need accusative:

• u torbicu

Compare:

• Stavit ću kusur u torbicu. = I’ll put the change into the handbag.
• Kusur je u torbici. = The change is in the handbag.

So:

• u torbicu = into the handbag
• u torbici = in the handbag

Also, torbica usually means a small bag, handbag, or purse, not a large bag.

Kusur means change, as in the money you get back after paying.

Example:

• If something costs 8 euros and you give 10, the 2 euros you get back are kusur.

Common examples:

• Imate li kusur? = Do you have change?
• Vratio mi je kusur. = He gave me my change back.

A useful distinction:

• kusur = change returned after payment
• sitniš = small coins / loose change

They are related, but not always exactly the same.

Račun is a very common Croatian word with several meanings, depending on context:

• receipt
• bill
• check in a restaurant
• invoice
• account
• sometimes even calculation

In this sentence, because we have kusur and shopping/payment context, račun most likely means receipt.

So:

• spremiti račun = put away the receipt / keep the receipt

In another context:

• Platiti račun = pay the bill
• Bankovni račun = bank account

So learners need to rely on context to decide which English word fits.

No. In this sentence, spremiti means something like:

• put away
• store
• put somewhere safe
• keep

So:

• spremiti račun = put away the receipt or keep the receipt

This is different from the English verb prepare.

Croatian spremiti can mean:

• to put away
• to tidy away
• to store
• in some contexts, to prepare or get ready

Here, with račun, the meaning is clearly put away / save.

A close English equivalent would be:

• I’ll put the receipt away or
• I’ll keep the receipt

Because these are perfective verbs, and the sentence talks about single completed actions.

• doći = to arrive, to come
• staviti = to put
• spremiti = to put away / store

Each action is seen as a whole:

1. I arrive home
2. I put the change in my handbag
3. I put away the receipt

That is why perfective verbs fit well.

Compare the imperfective partners:

• dolaziti = to be coming / to come repeatedly
• stavljati = to be putting / to put repeatedly
• spremati = to be putting away / preparing / doing repeatedly or as a process

Using imperfective here would change the feel of the sentence and make it sound more like an ongoing or repeated action rather than a simple one-time event.

Yes, it is normal and natural.

Croatian word order is more flexible than English, but this sentence follows a very common pattern:

• Kad budem došla kući = time clause first
• stavit ću kusur u torbicu i spremiti račun = main clause second

This is a natural way to organize the information:

1. first say when
2. then say what will happen

You could rearrange parts for emphasis, but the given order is perfectly standard and easy to understand.